Rectangular-to-rectangular duct adapter 3D models

First model: 2025-11-25
Number of 3D models generated: 113
Build this model to your specs

Category: technical parts

gizmo
Example of a 3D model generated using this template
(model #3981)

Photos of various 3D printed models

rectangular-to-rectangular duct adapter
#3876
rectangular-to-rectangular duct adapter
#3644
rectangular-to-rectangular duct adapter
#3872
rectangular-to-rectangular duct adapter
#3738
rectangular-to-rectangular duct adapter
#3870
rectangular-to-rectangular duct adapter
#3771
Keywords: rectangular duct adapter, rectangular sleeve, rectangular duct sleeve, rectangular fitting, rectangular duct fitting

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Enter at least one field.
If the model doesn’t exist, on-demand generation will be offered to you.
name unit Value
#1 side A internal width
20 to 300 – up to 1 decimal place
mm
#2 side A internal height
20 to 300 – up to 1 decimal place
mm
#3 sleeve length on side A
5 to 100 – up to 1 decimal place
mm
#4 side B internal width
20 to 300 – up to 1 decimal place
mm
#5 side B internal height
20 to 300 – up to 1 decimal place
mm
#6 sleeve length on side B
5 to 100 – up to 1 decimal place
mm
#7 thickness
1 to 8 - integer
mm
#8 transition length
20 to 300 – up to 1 decimal place
mm
#9 Y offset
0 to 300 – up to 1 decimal place
mm
#10 Z offset
0 to 300 – up to 1 decimal place
mm
#11 end chamfers - -
illustration of the parameters rectangular-to-rectangular duct adapter

The latest online-generated models

Rectangular pipe adapter STL file 220x90 mm to 220x40 mm – transition: 100 mm (📦 #9230)

1 object(s) - format STL
Rectangular pipe adapter STL file 220x90 mm to 220x40 mm – transition: 100 mm
Rectangular adapter exported as STL 3D file. Side A offers an internal cross-section of 220x90 mm (rectangular) and side B uses 220x40 mm (rectangular). On side A, the sleeve length is 30 mm, and on side B it is 50 mm. The transition section between the two sides is 100 mm long, for an overall length of 180 mm (side A sleeve, transition and side B sleeve). External chamfers are added at the ends to make it easier to push the adapter into ducts or pipes. Side B is offset by 50 mm along the Y axis relative to side A.
Parameter Value Unit
side A internal width 220 mm
side A internal height 90 mm
sleeve length on side A 30 mm
side B internal width 220 mm
side B internal height 40 mm
sleeve length on side B 50 mm
thickness 3 mm
transition length 100 mm
Y offset 50 mm
Z offset 0 mm
end chamfers outside

Rectangular pipe adapter STL file 300x21 mm to 100x42 mm – transition: 20 mm (📦 #9130)

1 object(s) - format STL
Rectangular pipe adapter STL file 300x21 mm to 100x42 mm – transition: 20 mm
Rectangular vent adapter provided as 3D STL file. The internal cross-section on side A is 300x21 mm (rectangular), while side B is 100x42 mm (rectangular). Both side A and side B sleeves share the same insertion length of 10 mm. The transition section between the two sides is 20 mm long, for an overall length of 40 mm (side A sleeve, transition and side B sleeve). Internal chamfers are added at the ends to make assembly and duct insertion easier.
Parameter Value Unit
side A internal width 300 mm
side A internal height 21 mm
sleeve length on side A 10 mm
side B internal width 100 mm
side B internal height 42 mm
sleeve length on side B 10 mm
thickness 2 mm
transition length 20 mm
Y offset 0 mm
Z offset 0 mm
end chamfers inside

Rectangular tube adapter STL 3D file 87x202 mm to 90x220 mm – transition: 20 mm (📦 #8885)

1 object(s) - format STL
Rectangular tube adapter STL 3D file 87x202 mm to 90x220 mm – transition: 20 mm
3D STL file for rectangular conduit adapter. Side A uses an internal cross-section of 87x202 mm (rectangular), whereas side B is 90x220 mm (rectangular). The sleeve insertion length is the same on both sides, 20 mm. The transition section runs for 20 mm and the overall length is 60 mm, sleeves included. Internal chamfers at the ends improve assembly and provide a smoother insertion of the mating duct.
Parameter Value Unit
side A internal width 87 mm
side A internal height 202 mm
sleeve length on side A 20 mm
side B internal width 90 mm
side B internal height 220 mm
sleeve length on side B 20 mm
thickness 2 mm
transition length 20 mm
Y offset 0 mm
Z offset 0 mm
end chamfers inside

Rectangle-to-rectangle duct adapter STL 3D file 50.5x50.5 mm to 43x43 mm – transition: 20 mm (📦 #8634)

1 object(s) - format STL
Rectangle-to-rectangle duct adapter STL 3D file 50.5x50.5 mm to 43x43 mm – transition: 20 mm
3D STL file for rectangular duct fitting. Side A offers an internal cross-section of 50.5x50.5 mm (square) and side B uses 43x43 mm (square). Each sleeve provides an insertion length of 20 mm. The transition section runs for 20 mm and the overall length is 60 mm, sleeves included. External chamfers at the ends help the adapter slide and seat more easily in the duct system.
Parameter Value Unit
side A internal width 50.5 mm
side A internal height 50.5 mm
sleeve length on side A 20 mm
side B internal width 43 mm
side B internal height 43 mm
sleeve length on side B 20 mm
thickness 3 mm
transition length 20 mm
Y offset 0 mm
Z offset 0 mm
end chamfers outside

Rectangular duct adapter STL 3D file 50x50 mm to 43x43 mm – transition: 20 mm (📦 #8630)

1 object(s) - format STL
Rectangular duct adapter STL 3D file 50x50 mm to 43x43 mm – transition: 20 mm
Rectangular adapter exported as STL 3D file. Side A offers an internal cross-section of 50x50 mm (square) and side B uses 43x43 mm (square). Both side A and side B sleeves share the same insertion length of 20 mm. Between the two sleeves, the transition section adds 20 mm, giving an overall length of 60 mm. External chamfers are added at the ends to make it easier to push the adapter into ducts or pipes.
Parameter Value Unit
side A internal width 50 mm
side A internal height 50 mm
sleeve length on side A 20 mm
side B internal width 43 mm
side B internal height 43 mm
sleeve length on side B 20 mm
thickness 3 mm
transition length 20 mm
Y offset 0 mm
Z offset 0 mm
end chamfers outside

Rectangular duct adapter STL 3D file 50x50 mm to 43x43 mm – transition: 20 mm (📦 #8628)

1 object(s) - format STL
Rectangular duct adapter STL 3D file 50x50 mm to 43x43 mm – transition: 20 mm
3D STL file for rectangular duct fitting. Side A uses an internal cross-section of 50x50 mm (square), whereas side B is 43x43 mm (square). The sleeve insertion length is the same on both sides, 20 mm. Between the two sleeves, the transition section adds 20 mm, giving an overall length of 60 mm. No chamfers are applied at the ends; both inner and outer edges remain sharp.
Parameter Value Unit
side A internal width 50 mm
side A internal height 50 mm
sleeve length on side A 20 mm
side B internal width 43 mm
side B internal height 43 mm
sleeve length on side B 20 mm
thickness 3 mm
transition length 20 mm
Y offset 0 mm
Z offset 0 mm
end chamfers none

Rectangle-to-rectangle duct adapter STL 3D file 50x50 mm to 43x43 mm – transition: 50 mm (📦 #8627)

1 object(s) - format STL
Rectangle-to-rectangle duct adapter STL 3D file 50x50 mm to 43x43 mm – transition: 50 mm
Rectangular conduit adapter exported as STL 3D file. The internal cross-section on side A is 50x50 mm (square), while side B is 43x43 mm (square). Both side A and side B sleeves share the same insertion length of 20 mm. The transition section between the two sides is 50 mm long, for an overall length of 90 mm (side A sleeve, transition and side B sleeve). No chamfers are applied at the ends; both inner and outer edges remain sharp.
Parameter Value Unit
side A internal width 50 mm
side A internal height 50 mm
sleeve length on side A 20 mm
side B internal width 43 mm
side B internal height 43 mm
sleeve length on side B 20 mm
thickness 3 mm
transition length 50 mm
Y offset 0 mm
Z offset 0 mm
end chamfers none

Rectangular pipe adapter STL 3D file 150x150 mm to 220x150 mm – transition: 20 mm (📦 #7852)

1 object(s) - format STL
Rectangular pipe adapter STL 3D file 150x150 mm to 220x150 mm – transition: 20 mm
3D STL file for rectangular adapter. The internal cross-section on side A is 150x150 mm (square), while side B is 220x150 mm (rectangular). The sleeve on side A provides an insertion length of 9 mm, and the sleeve on side B 60 mm. Between the two sleeves, the transition section adds 20 mm, giving an overall length of 89 mm. Internal chamfers are added at the ends to make assembly and duct insertion easier.
Parameter Value Unit
side A internal width 150 mm
side A internal height 150 mm
sleeve length on side A 9 mm
side B internal width 220 mm
side B internal height 150 mm
sleeve length on side B 60 mm
thickness 2 mm
transition length 20 mm
Y offset 0 mm
Z offset 0 mm
end chamfers inside

Rectangular pipe adapter STL 3D file 150x150 mm to 150x150 mm – transition: 20 mm (📦 #7850)

1 object(s) - format STL
Rectangular pipe adapter STL 3D file 150x150 mm to 150x150 mm – transition: 20 mm
Rectangular duct sleeve exported as STL 3D file. Both ends have the same internal cross-section, 150x150 mm, with a square shape. Each sleeve provides an insertion length of 35 mm. The transition section runs for 20 mm and the overall length is 90 mm, sleeves included. Internal chamfers are added at the ends to make assembly and duct insertion easier.
Parameter Value Unit
side A internal width 150 mm
side A internal height 150 mm
sleeve length on side A 35 mm
side B internal width 150 mm
side B internal height 150 mm
sleeve length on side B 35 mm
thickness 2 mm
transition length 20 mm
Y offset 0 mm
Z offset 0 mm
end chamfers inside

Rectangular pipe adapter STL 3D file 150x150 mm to 150x150 mm – transition: 90 mm (📦 #7849)

1 object(s) - format STL
Rectangular pipe adapter STL 3D file 150x150 mm to 150x150 mm – transition: 90 mm
Rectangular pipe adapter downloadable as STL 3D file. Both ends have the same internal cross-section, 150x150 mm, with a square shape. Each sleeve provides an insertion length of 45 mm. The transition section runs for 90 mm and the overall length is 180 mm, sleeves included. The internal edges at the ends are chamfered to help guide the duct during insertion.
Parameter Value Unit
side A internal width 150 mm
side A internal height 150 mm
sleeve length on side A 45 mm
side B internal width 150 mm
side B internal height 150 mm
sleeve length on side B 45 mm
thickness 2 mm
transition length 90 mm
Y offset 0 mm
Z offset 0 mm
end chamfers inside

Rectangle-to-rectangle duct adapter STL 3D file 122x61 mm to 114x54 mm – transition: 140 mm (📦 #7221)

1 object(s) - format STL
Rectangle-to-rectangle duct adapter STL 3D file 122x61 mm to 114x54 mm – transition: 140 mm
Rectangular duct fitting provided as 3D STL file. The internal cross-section on side A is 122x61 mm (rectangular), while side B is 114x54 mm (rectangular). Both side A and side B sleeves share the same insertion length of 30 mm. The transition section runs for 140 mm and the overall length is 200 mm, sleeves included. Inner and outer edges at both ends are left unchamfered. Side B is offset by 70 mm along the Y axis and 35 mm along the Z axis relative to side A.
Parameter Value Unit
side A internal width 122 mm
side A internal height 61 mm
sleeve length on side A 30 mm
side B internal width 114 mm
side B internal height 54 mm
sleeve length on side B 30 mm
thickness 3 mm
transition length 140 mm
Y offset 70 mm
Z offset 35 mm
end chamfers none

Rectangular tube adapter STL file 120x60 mm to 114x54 mm – transition: 140 mm (📦 #7219)

1 object(s) - format STL
Rectangular tube adapter STL file 120x60 mm to 114x54 mm – transition: 140 mm
3D STL file for rectangular tube adapter. Side A offers an internal cross-section of 120x60 mm (rectangular) and side B uses 114x54 mm (rectangular). Each sleeve provides an insertion length of 30 mm. Between the two sleeves, the transition section adds 140 mm, giving an overall length of 200 mm. External chamfers are added at the ends to make it easier to push the adapter into ducts or pipes. An offset of 35 mm along the Y axis and 70 mm along the Z axis is applied to side B with respect to side A.
Parameter Value Unit
side A internal width 120 mm
side A internal height 60 mm
sleeve length on side A 30 mm
side B internal width 114 mm
side B internal height 54 mm
sleeve length on side B 30 mm
thickness 3 mm
transition length 140 mm
Y offset 35 mm
Z offset 70 mm
end chamfers outside

Rectangular pipe adapter STL file 122.3x60.3 mm to 116x56 mm – transition: 20 mm (📦 #7196)

1 object(s) - format STL
Rectangular pipe adapter STL file 122.3x60.3 mm to 116x56 mm – transition: 20 mm
3D STL file for rectangular duct connector. Side A uses an internal cross-section of 122.3x60.3 mm (rectangular), whereas side B is 116x56 mm (rectangular). The sleeve on side A provides an insertion length of 25 mm, and the sleeve on side B 30 mm. Between the two sleeves, the transition section adds 20 mm, giving an overall length of 75 mm. Internal chamfers are added at the ends to make assembly and duct insertion easier.
Parameter Value Unit
side A internal width 122.3 mm
side A internal height 60.3 mm
sleeve length on side A 25 mm
side B internal width 116 mm
side B internal height 56 mm
sleeve length on side B 30 mm
thickness 2 mm
transition length 20 mm
Y offset 0 mm
Z offset 0 mm
end chamfers inside

Rectangular tube adapter STL 3D file 122.3x60.3 mm to 116.3x56.3 mm – transition: 20 mm (📦 #7193)

1 object(s) - format STL
Rectangular tube adapter STL 3D file 122.3x60.3 mm to 116.3x56.3 mm – transition: 20 mm
Rectangular duct fitting provided as 3D STL file. The internal cross-section on side A is 122.3x60.3 mm (rectangular), while side B is 116.3x56.3 mm (rectangular). The insertion length on side A is 25 mm, while on side B it is 30 mm. The transition section runs for 20 mm and the overall length is 75 mm, sleeves included. The internal edges at the ends are chamfered to help guide the duct during insertion.
Parameter Value Unit
side A internal width 122.3 mm
side A internal height 60.3 mm
sleeve length on side A 25 mm
side B internal width 116.3 mm
side B internal height 56.3 mm
sleeve length on side B 30 mm
thickness 2 mm
transition length 20 mm
Y offset 0 mm
Z offset 0 mm
end chamfers inside

Rectangular tube adapter STL file 115x115 mm to 225x90 mm – transition: 140 mm (📦 #7034)

1 object(s) - format STL
Rectangular tube adapter STL file 115x115 mm to 225x90 mm – transition: 140 mm
3D STL file for rectangular duct sleeve. Side A offers an internal cross-section of 115x115 mm (square) and side B uses 225x90 mm (rectangular). Each sleeve provides an insertion length of 40 mm. Between the two sleeves, the transition section adds 140 mm, giving an overall length of 220 mm. External chamfers at the ends help the adapter slide and seat more easily in the duct system.
Parameter Value Unit
side A internal width 115 mm
side A internal height 115 mm
sleeve length on side A 40 mm
side B internal width 225 mm
side B internal height 90 mm
sleeve length on side B 40 mm
thickness 3 mm
transition length 140 mm
Y offset 0 mm
Z offset 0 mm
end chamfers outside

Rectangle-to-rectangle duct adapter STL file 90x220 mm to 220x90 mm – transition: 140 mm (📦 #7029)

1 object(s) - format STL
Rectangle-to-rectangle duct adapter STL file 90x220 mm to 220x90 mm – transition: 140 mm
Rectangular duct sleeve downloadable as STL 3D file. Side A offers an internal cross-section of 90x220 mm (rectangular) and side B uses 220x90 mm (rectangular). Each sleeve provides an insertion length of 40 mm. Between the two sleeves, the transition section adds 140 mm, giving an overall length of 220 mm. External chamfers are added at the ends to make it easier to push the adapter into ducts or pipes.
Parameter Value Unit
side A internal width 90 mm
side A internal height 220 mm
sleeve length on side A 40 mm
side B internal width 220 mm
side B internal height 90 mm
sleeve length on side B 40 mm
thickness 3 mm
transition length 140 mm
Y offset 0 mm
Z offset 0 mm
end chamfers outside

Rectangular duct adapter STL 3D file 120x120 mm to 94x94 mm – transition: 20 mm (📦 #6955)

1 object(s) - format STL
Rectangular duct adapter STL 3D file 120x120 mm to 94x94 mm – transition: 20 mm
Rectangular duct adapter downloadable as STL 3D file. The internal cross-section on side A is 120x120 mm (square), while side B is 94x94 mm (square). The insertion length on side A is 40 mm, while on side B it is 24 mm. Between the two sleeves, the transition section adds 20 mm, giving an overall length of 84 mm. Wall thickness is minimal at 1 mm. Internal chamfers are added at the ends to make assembly and duct insertion easier.
Parameter Value Unit
side A internal width 120 mm
side A internal height 120 mm
sleeve length on side A 40 mm
side B internal width 94 mm
side B internal height 94 mm
sleeve length on side B 24 mm
thickness 1 mm
transition length 20 mm
Y offset 0 mm
Z offset 0 mm
end chamfers inside

Rectangular pipe adapter STL file 74x49 mm to 110x55 mm – transition: 300 mm (📦 #6457)

1 object(s) - format STL
Rectangular pipe adapter STL file 74x49 mm to 110x55 mm – transition: 300 mm
Rectangular adapter downloadable as STL 3D file. Side A offers an internal cross-section of 74x49 mm (rectangular) and side B uses 110x55 mm (rectangular). Each sleeve provides an insertion length of 100 mm. The transition section between the two sides is 300 mm long, for an overall length of 500 mm (side A sleeve, transition and side B sleeve). Wall thickness is minimal at 1 mm. The internal edges at the ends are chamfered to help guide the duct during insertion. Side B is offset by 150 mm along the Y axis and 150 mm along the Z axis relative to side A.
Parameter Value Unit
side A internal width 74 mm
side A internal height 49 mm
sleeve length on side A 100 mm
side B internal width 110 mm
side B internal height 55 mm
sleeve length on side B 100 mm
thickness 1 mm
transition length 300 mm
Y offset 150 mm
Z offset 150 mm
end chamfers inside

Rectangular duct adapter STL file 100x60 mm to 100x60 mm – transition: 20 mm (📦 #6424)

1 object(s) - format STL
Rectangular duct adapter STL file 100x60 mm to 100x60 mm – transition: 20 mm
Rectangular pipe adapter provided as 3D STL file. Side A and side B share the same internal cross-section, 100x60 mm, with a rectangular profile. The sleeve on side A provides an insertion length of 30 mm, and the sleeve on side B 70 mm. Between the two sleeves, the transition section adds 20 mm, giving an overall length of 120 mm. The ends are left without chamfers, with sharp inner and outer edges.
Parameter Value Unit
side A internal width 100 mm
side A internal height 60 mm
sleeve length on side A 30 mm
side B internal width 100 mm
side B internal height 60 mm
sleeve length on side B 70 mm
thickness 2 mm
transition length 20 mm
Y offset 0 mm
Z offset 0 mm
end chamfers none

Rectangular pipe adapter STL 3D file 295x291 mm to 130x130 mm – transition: 25 mm (📦 #6175)

1 object(s) - format STL
Rectangular pipe adapter STL 3D file 295x291 mm to 130x130 mm – transition: 25 mm
Rectangular duct transition downloadable as STL 3D file. The internal cross-section on side A is 295x291 mm (rectangular), while side B is 130x130 mm (square). The sleeve insertion length is the same on both sides, 30 mm. Between the two sleeves, the transition section adds 25 mm, giving an overall length of 85 mm. The shell is thick, with a wall thickness of 5 mm. The ends are left without chamfers, with sharp inner and outer edges.
Parameter Value Unit
side A internal width 295 mm
side A internal height 291 mm
sleeve length on side A 30 mm
side B internal width 130 mm
side B internal height 130 mm
sleeve length on side B 30 mm
thickness 5 mm
transition length 25 mm
Y offset 0 mm
Z offset 0 mm
end chamfers none

Rectangular tube adapter STL 3D file 242x138 mm to 124.6x129 mm – transition: 60 mm (📦 #5969)

1 object(s) - format STL
Rectangular tube adapter STL 3D file 242x138 mm to 124.6x129 mm – transition: 60 mm
Rectangular duct sleeve downloadable as STL 3D file. The internal cross-section on side A is 242x138 mm (rectangular), while side B is 124.6x129 mm (rectangular). Both side A and side B sleeves share the same insertion length of 5 mm. The transition section between the two sides is 60 mm long, for an overall length of 70 mm (side A sleeve, transition and side B sleeve). Internal chamfers are added at the ends to make assembly and duct insertion easier.
Parameter Value Unit
side A internal width 242 mm
side A internal height 138 mm
sleeve length on side A 5 mm
side B internal width 124.6 mm
side B internal height 129 mm
sleeve length on side B 5 mm
thickness 2 mm
transition length 60 mm
Y offset 0 mm
Z offset 0 mm
end chamfers inside

Rectangular tube adapter STL 3D file 242x138 mm to 124.6x129 mm – transition: 40 mm (📦 #5968)

1 object(s) - format STL
Rectangular tube adapter STL 3D file 242x138 mm to 124.6x129 mm – transition: 40 mm
Rectangular duct sleeve provided as 3D STL file. The internal cross-section on side A is 242x138 mm (rectangular), while side B is 124.6x129 mm (rectangular). Each sleeve provides an insertion length of 5 mm. The transition section runs for 40 mm and the overall length is 50 mm, sleeves included. Internal chamfers are added at the ends to make assembly and duct insertion easier.
Parameter Value Unit
side A internal width 242 mm
side A internal height 138 mm
sleeve length on side A 5 mm
side B internal width 124.6 mm
side B internal height 129 mm
sleeve length on side B 5 mm
thickness 2 mm
transition length 40 mm
Y offset 0 mm
Z offset 0 mm
end chamfers inside

Rectangular tube adapter STL file 242x138 mm to 123.6x128 mm – transition: 40 mm (📦 #5904)

1 object(s) - format STL
Rectangular tube adapter STL file 242x138 mm to 123.6x128 mm – transition: 40 mm
Rectangular adapter exported as STL 3D file. The internal cross-section on side A is 242x138 mm (rectangular), while side B is 123.6x128 mm (rectangular). Both side A and side B sleeves share the same insertion length of 5 mm. The transition section between the two sides is 40 mm long, for an overall length of 50 mm (side A sleeve, transition and side B sleeve). Internal chamfers are added at the ends to make assembly and duct insertion easier.
Parameter Value Unit
side A internal width 242 mm
side A internal height 138 mm
sleeve length on side A 5 mm
side B internal width 123.6 mm
side B internal height 128 mm
sleeve length on side B 5 mm
thickness 2 mm
transition length 40 mm
Y offset 0 mm
Z offset 0 mm
end chamfers inside

Rectangular pipe adapter STL 3D file 242x138 mm to 123.6x127 mm – transition: 40 mm (📦 #5903)

1 object(s) - format STL
Rectangular pipe adapter STL 3D file 242x138 mm to 123.6x127 mm – transition: 40 mm
Rectangular duct sleeve downloadable as STL 3D file. The internal cross-section on side A is 242x138 mm (rectangular), while side B is 123.6x127 mm (rectangular). The sleeve insertion length is the same on both sides, 5 mm. The transition section between the two sides is 40 mm long, for an overall length of 50 mm (side A sleeve, transition and side B sleeve). The internal edges at the ends are chamfered to help guide the duct during insertion.
Parameter Value Unit
side A internal width 242 mm
side A internal height 138 mm
sleeve length on side A 5 mm
side B internal width 123.6 mm
side B internal height 127 mm
sleeve length on side B 5 mm
thickness 2 mm
transition length 40 mm
Y offset 0 mm
Z offset 0 mm
end chamfers inside

Rectangular tube adapter STL 3D file 242x138 mm to 123.6x124.6 mm – transition: 40 mm (📦 #5902)

1 object(s) - format STL
Rectangular tube adapter STL 3D file 242x138 mm to 123.6x124.6 mm – transition: 40 mm
3D STL file for rectangular duct adapter. Side A offers an internal cross-section of 242x138 mm (rectangular) and side B uses 123.6x124.6 mm (rectangular). Both side A and side B sleeves share the same insertion length of 5 mm. The transition section between the two sides is 40 mm long, for an overall length of 50 mm (side A sleeve, transition and side B sleeve). Internal chamfers at the ends improve assembly and provide a smoother insertion of the mating duct.
Parameter Value Unit
side A internal width 242 mm
side A internal height 138 mm
sleeve length on side A 5 mm
side B internal width 123.6 mm
side B internal height 124.6 mm
sleeve length on side B 5 mm
thickness 2 mm
transition length 40 mm
Y offset 0 mm
Z offset 0 mm
end chamfers inside

Rectangular pipe adapter STL file 246x142 mm to 123.6x124.6 mm – transition: 20 mm (📦 #5901)

1 object(s) - format STL
Rectangular pipe adapter STL file 246x142 mm to 123.6x124.6 mm – transition: 20 mm
Rectangular duct fitting exported as STL 3D file. The internal cross-section on side A is 246x142 mm (rectangular), while side B is 123.6x124.6 mm (rectangular). Both side A and side B sleeves share the same insertion length of 5 mm. Between the two sleeves, the transition section adds 20 mm, giving an overall length of 30 mm. Internal chamfers at the ends improve assembly and provide a smoother insertion of the mating duct.
Parameter Value Unit
side A internal width 246 mm
side A internal height 142 mm
sleeve length on side A 5 mm
side B internal width 123.6 mm
side B internal height 124.6 mm
sleeve length on side B 5 mm
thickness 2 mm
transition length 20 mm
Y offset 0 mm
Z offset 0 mm
end chamfers inside

Rectangle-to-rectangle duct adapter STL file 100x100 mm to 50.5x50.5 mm – transition: 25 mm (📦 #5839)

1 object(s) - format STL
Rectangle-to-rectangle duct adapter STL file 100x100 mm to 50.5x50.5 mm – transition: 25 mm
3D STL file for rectangular vent adapter. Side A uses an internal cross-section of 100x100 mm (square), whereas side B is 50.5x50.5 mm (square). The sleeve on side A provides an insertion length of 50 mm, and the sleeve on side B 25 mm. The transition section between the two sides is 25 mm long, for an overall length of 100 mm (side A sleeve, transition and side B sleeve). Internal chamfers at the ends improve assembly and provide a smoother insertion of the mating duct.
Parameter Value Unit
side A internal width 100 mm
side A internal height 100 mm
sleeve length on side A 50 mm
side B internal width 50.5 mm
side B internal height 50.5 mm
sleeve length on side B 25 mm
thickness 3 mm
transition length 25 mm
Y offset 0 mm
Z offset 0 mm
end chamfers inside

Rectangular tube adapter STL 3D file 150x150 mm to 55x55 mm – transition: 25 mm (📦 #5825)

1 object(s) - format STL
Rectangular tube adapter STL 3D file 150x150 mm to 55x55 mm – transition: 25 mm
Rectangular duct fitting exported as STL 3D file. The internal cross-section on side A is 150x150 mm (square), while side B is 55x55 mm (square). The insertion length on side A is 50 mm, while on side B it is 25 mm. Between the two sleeves, the transition section adds 25 mm, giving an overall length of 100 mm. The internal edges at the ends are chamfered to help guide the duct during insertion.
Parameter Value Unit
side A internal width 150 mm
side A internal height 150 mm
sleeve length on side A 50 mm
side B internal width 55 mm
side B internal height 55 mm
sleeve length on side B 25 mm
thickness 3 mm
transition length 25 mm
Y offset 0 mm
Z offset 0 mm
end chamfers inside

Rectangle-to-rectangle duct adapter STL 3D file 200x200 mm to 56x56 mm – transition: 40 mm (📦 #5821)

1 object(s) - format STL
Rectangle-to-rectangle duct adapter STL 3D file 200x200 mm to 56x56 mm – transition: 40 mm
3D STL file for rectangular tube adapter. Side A uses an internal cross-section of 200x200 mm (square), whereas side B is 56x56 mm (square). On side A, the sleeve length is 50 mm, and on side B it is 25 mm. The transition section runs for 40 mm and the overall length is 115 mm, sleeves included. Wall thickness is generous (4 mm). The internal edges at the ends are chamfered to help guide the duct during insertion.
Parameter Value Unit
side A internal width 200 mm
side A internal height 200 mm
sleeve length on side A 50 mm
side B internal width 56 mm
side B internal height 56 mm
sleeve length on side B 25 mm
thickness 4 mm
transition length 40 mm
Y offset 0 mm
Z offset 0 mm
end chamfers inside

Rectangular tube adapter STL file 106x51 mm to 106x51 mm – transition: 240 mm (📦 #5370)

1 object(s) - format STL
Rectangular tube adapter STL file 106x51 mm to 106x51 mm – transition: 240 mm
3D STL file for rectangular tube adapter. Side A and side B share the same internal cross-section, 106x51 mm, with a rectangular profile. Each sleeve provides an insertion length of 30 mm. Between the two sleeves, the transition section adds 240 mm, giving an overall length of 300 mm. No chamfers are applied at the ends; both inner and outer edges remain sharp. An offset of 100 mm along the Z axis is applied to side B with respect to side A.
Parameter Value Unit
side A internal width 106 mm
side A internal height 51 mm
sleeve length on side A 30 mm
side B internal width 106 mm
side B internal height 51 mm
sleeve length on side B 30 mm
thickness 2 mm
transition length 240 mm
Y offset 0 mm
Z offset 100 mm
end chamfers none

Use cases for Rectangle-to-Rectangle duct adapters

Rectangle-to-rectangle adapters make it possible to connect two ducts of similar shape but different dimensions while keeping a smooth, controlled transition. The parametric design lets you fine-tune the internal sections, sleeve lengths, wall thickness, and the transition length, ensuring a part that fits the installation requirements with precision.

For a significant size reduction, the adapter 200×90 mm to 80×80 mm shows how the template handles large differences between the two openings while maintaining a gentle transition and consistent structural strength. Conversely, for a simple and compact reduction, the model 90×90 mm to 80×80 mm offers a short, efficient geometry with no offset, ideal where space is limited.

When the ducts cannot be aligned on the same axis, the system can generate a shifted (offset) adapter. The model 60×60 mm with offset is a typical example, making installation easier in setups that require a mechanical offset. And for long, gradual transitions, the adapter 60×60 mm to 80×80 mm (180 mm transition) demonstrates how extended profiles help smooth airflow changes or bypass space constraints.