Rectangular-to-rectangular duct adapter 3D models

First model: 2025-11-25

Number of 3D models generated: 144

Category: technical parts

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Photos of various 3D printed models

This template generates rectangular-to-rectangular duct adapters. For each side, the length, height, and sleeve depth of the connector can be adjusted.

To fit a wide range of setups, the length of the transition between both sleeves is also adjustable, as well as the shell thickness and the optional chamfer at the ends to ease insertion.

Finally, you can apply an offset along the Y and Z axes.

Keywords: rectangular duct adapter, rectangular sleeve, rectangular duct sleeve, rectangular fitting, rectangular duct fitting

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	name	unit	Value	Weight
#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		-	-
			Search

Illustration of the parameters

The latest online-generated models

Rectangle-to-rectangle duct adapter STL 3D file 164.2x68 mm to 164x67.8 mm – transition: 20 mm (📦 #10260)

1 object(s) - format STL

Rectangular duct adapter provided as 3D STL file. Side A offers an internal cross-section of 164.2x68 mm (rectangular) and side B uses 164x67.8 mm (rectangular). On side A, the sleeve length is 80 mm, and on side B it is 100 mm. The transition section between the two sides is 20 mm long, for an overall length of 200 mm (side A sleeve, transition and side B sleeve). The shell is kept very light, with only 1 mm wall thickness. The internal edges at the ends are chamfered to help guide the duct during insertion.

Parameter	Value	Unit
side A internal width	164.2	mm
side A internal height	68	mm
sleeve length on side A	80	mm
side B internal width	164	mm
side B internal height	67.8	mm
sleeve length on side B	100	mm
thickness	1	mm
transition length	20	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	inside

Rectangular tube adapter STL 3D file 214x87 mm to 215x87 mm – transition: 20 mm (📦 #10241)

1 object(s) - format STL

Rectangular pipe adapter provided as 3D STL file. Side A offers an internal cross-section of 214x87 mm (rectangular) and side B uses 215x87 mm (rectangular). Each sleeve provides an 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	214	mm
side A internal height	87	mm
sleeve length on side A	5	mm
side B internal width	215	mm
side B internal height	87	mm
sleeve length on side B	5	mm
thickness	3	mm
transition length	20	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	inside

Rectangular duct adapter STL 3D file 214x85 mm to 215x85 mm – transition: 20 mm (📦 #10239)

1 object(s) - format STL

Rectangular vent adapter exported as STL 3D file. Side A offers an internal cross-section of 214x85 mm (rectangular) and side B uses 215x85 mm (rectangular). The sleeve insertion length is the same on both sides, 5 mm. Between the two sleeves, the transition section adds 20 mm, giving an overall length of 30 mm. The internal edges at the ends are chamfered to help guide the duct during insertion.

Parameter	Value	Unit
side A internal width	214	mm
side A internal height	85	mm
sleeve length on side A	5	mm
side B internal width	215	mm
side B internal height	85	mm
sleeve length on side B	5	mm
thickness	3	mm
transition length	20	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	inside

Rectangular tube adapter STL 3D file 214x83 mm to 215x83 mm – transition: 20 mm (📦 #10238)

1 object(s) - format STL

Rectangular adapter downloadable as STL 3D file. The internal cross-section on side A is 214x83 mm (rectangular), while side B is 215x83 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. External chamfers at the ends help the adapter slide and seat more easily in the duct system.

Parameter	Value	Unit
side A internal width	214	mm
side A internal height	83	mm
sleeve length on side A	5	mm
side B internal width	215	mm
side B internal height	83	mm
sleeve length on side B	5	mm
thickness	3	mm
transition length	20	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	outside

Rectangular pipe adapter STL file 215x90 mm to 215x90 mm – transition: 20 mm (📦 #10237)

1 object(s) - format STL

Rectangular adapter provided as 3D STL file. On both side A and side B, the internal cross-section is 215x90 mm, with a rectangular geometry. The sleeve insertion length is the same on both sides, 5 mm. The transition section between the two sides is 20 mm long, for an overall length of 30 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	215	mm
side A internal height	90	mm
sleeve length on side A	5	mm
side B internal width	215	mm
side B internal height	90	mm
sleeve length on side B	5	mm
thickness	3	mm
transition length	20	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	inside

Rectangle-to-rectangle duct adapter STL 3D file 111.4x54.4 mm to 110.4x54.4 mm – transition: 20 mm (📦 #9918)

1 object(s) - format STL

Rectangular adapter exported as STL 3D file. Side A uses an internal cross-section of 111.4x54.4 mm (rectangular), whereas side B is 110.4x54.4 mm (rectangular). Both side A and side B sleeves share the same insertion length of 25 mm. The transition section runs for 20 mm and the overall length is 70 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	111.4	mm
side A internal height	54.4	mm
sleeve length on side A	25	mm
side B internal width	110.4	mm
side B internal height	54.4	mm
sleeve length on side B	25	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 70x70 mm to 37x36 mm – transition: 20 mm (📦 #9719)

1 object(s) - format STL

Rectangular tube adapter exported as STL 3D file. Side A uses an internal cross-section of 70x70 mm (square), whereas side B is 37x36 mm (rectangular). On side A, the sleeve length is 40 mm, and on side B it is 5 mm. The transition section runs for 20 mm and the overall length is 65 mm, sleeves included. Wall thickness is minimal at 1 mm. The ends are left without chamfers, with sharp inner and outer edges.

Parameter	Value	Unit
side A internal width	70	mm
side A internal height	70	mm
sleeve length on side A	40	mm
side B internal width	37	mm
side B internal height	36	mm
sleeve length on side B	5	mm
thickness	1	mm
transition length	20	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	none

Rectangle-to-rectangle duct adapter STL 3D file 214x84 mm to 198x54 mm – transition: 40 mm (📦 #9718)

1 object(s) - format STL

Rectangular adapter provided as 3D STL file. Side A uses an internal cross-section of 214x84 mm (rectangular), whereas side B is 198x54 mm (rectangular). On side A, the sleeve length is 30 mm, and on side B it is 40 mm. Between the two sleeves, the transition section adds 40 mm, giving an overall length of 110 mm. The outer edges at the ends are chamfered, which simplifies inserting the adapter into the mating duct. An offset of 16 mm along the Z axis is applied to side B with respect to side A.

Parameter	Value	Unit
side A internal width	214	mm
side A internal height	84	mm
sleeve length on side A	30	mm
side B internal width	198	mm
side B internal height	54	mm
sleeve length on side B	40	mm
thickness	3	mm
transition length	40	mm
Y offset	0	mm
Z offset	16	mm
end chamfers	outside

Rectangle-to-rectangle duct adapter STL file 220x90 mm to 205x60 mm – transition: 50 mm (📦 #9709)

1 object(s) - format STL

Rectangular duct connector provided as 3D STL file. Side A uses an internal cross-section of 220x90 mm (rectangular), whereas side B is 205x60 mm (rectangular). Both side A and side B sleeves share the same insertion length of 40 mm. Between the two sleeves, the transition section adds 50 mm, giving an overall length of 130 mm. Internal chamfers at the ends improve assembly and provide a smoother insertion of the mating duct. Side B is offset by 15 mm along the Z 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	40	mm
side B internal width	205	mm
side B internal height	60	mm
sleeve length on side B	40	mm
thickness	3	mm
transition length	50	mm
Y offset	0	mm
Z offset	15	mm
end chamfers	inside

Rectangular tube adapter STL 3D file 220x90 mm to 205x60 mm – transition: 50 mm (📦 #9685)

1 object(s) - format STL

Rectangular duct transition exported as STL 3D file. The internal cross-section on side A is 220x90 mm (rectangular), while side B is 205x60 mm (rectangular). Each sleeve provides an insertion length of 40 mm. The transition section between the two sides is 50 mm long, for an overall length of 130 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	220	mm
side A internal height	90	mm
sleeve length on side A	40	mm
side B internal width	205	mm
side B internal height	60	mm
sleeve length on side B	40	mm
thickness	3	mm
transition length	50	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	inside

Rectangle-to-rectangle duct adapter STL file 60x284.4 mm to 161.9x191 mm – transition: 50 mm (📦 #9631)

1 object(s) - format STL

Rectangular vent adapter exported as STL 3D file. The internal cross-section on side A is 60x284.4 mm (rectangular), while side B is 161.9x191 mm (rectangular). The insertion length on side A is 5 mm, while on side B it is 33.5 mm. The transition section between the two sides is 50 mm long, for an overall length of 88.5 mm (side A sleeve, transition and side B sleeve). The shell is thick, with a wall thickness of 4 mm. The internal edges at the ends are chamfered to help guide the duct during insertion. Relative to side A, side B is shifted by 25 mm along the Y axis.

Parameter	Value	Unit
side A internal width	60	mm
side A internal height	284.4	mm
sleeve length on side A	5	mm
side B internal width	161.9	mm
side B internal height	191	mm
sleeve length on side B	33.5	mm
thickness	4	mm
transition length	50	mm
Y offset	25	mm
Z offset	0	mm
end chamfers	inside

Rectangular tube adapter STL 3D file 60x284.4 mm to 161.9x191 mm – transition: 50 mm (📦 #9620)

1 object(s) - format STL

3D STL file for rectangular conduit adapter. The internal cross-section on side A is 60x284.4 mm (rectangular), while side B is 161.9x191 mm (rectangular). On side A, the sleeve length is 5 mm, and on side B it is 33.5 mm. The transition section runs for 50 mm and the overall length is 88.5 mm, sleeves included. The shell is thick, with a wall thickness of 5 mm. The internal edges at the ends are chamfered to help guide the duct during insertion. Side B is offset by 25 mm along the Y axis relative to side A.

Parameter	Value	Unit
side A internal width	60	mm
side A internal height	284.4	mm
sleeve length on side A	5	mm
side B internal width	161.9	mm
side B internal height	191	mm
sleeve length on side B	33.5	mm
thickness	5	mm
transition length	50	mm
Y offset	25	mm
Z offset	0	mm
end chamfers	inside

Rectangular tube adapter STL file 60x284.4 mm to 161.9x191 mm – transition: 50 mm (📦 #9619)

1 object(s) - format STL

Rectangular pipe adapter provided as 3D STL file. Side A offers an internal cross-section of 60x284.4 mm (rectangular) and side B uses 161.9x191 mm (rectangular). Each sleeve provides an insertion length of 5 mm. The transition section runs for 50 mm and the overall length is 60 mm, sleeves included. The wall is relatively thick, at 5 mm. Internal chamfers are added at the ends to make assembly and duct insertion easier. An offset of 25 mm along the Y axis is applied to side B with respect to side A.

Parameter	Value	Unit
side A internal width	60	mm
side A internal height	284.4	mm
sleeve length on side A	5	mm
side B internal width	161.9	mm
side B internal height	191	mm
sleeve length on side B	5	mm
thickness	5	mm
transition length	50	mm
Y offset	25	mm
Z offset	0	mm
end chamfers	inside

Rectangle-to-rectangle duct adapter STL file 50x20 mm to 40x20 mm – transition: 50 mm (📦 #9520)

1 object(s) - format STL

Rectangular duct adapter exported as STL 3D file. Side A uses an internal cross-section of 50x20 mm (rectangular), whereas side B is 40x20 mm (rectangular). On side A, the sleeve length is 5 mm, and on side B it is 80 mm. Between the two sleeves, the transition section adds 50 mm, giving an overall length of 135 mm. The ends are left without chamfers, with sharp inner and outer edges.

Parameter	Value	Unit
side A internal width	50	mm
side A internal height	20	mm
sleeve length on side A	5	mm
side B internal width	40	mm
side B internal height	20	mm
sleeve length on side B	80	mm
thickness	2	mm
transition length	50	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	none

Rectangular tube adapter STL 3D file 225x59.5 mm to 114.5x95 mm – transition: 20 mm (📦 #9467)

1 object(s) - format STL

3D STL file for rectangular duct fitting. The internal cross-section on side A is 225x59.5 mm (rectangular), while side B is 114.5x95 mm (rectangular). Each sleeve provides an insertion length of 20 mm. The transition section between the two sides is 20 mm long, for an overall length of 60 mm (side A sleeve, transition and side B sleeve). The wall is thin, with a thickness of 1 mm. The internal edges at the ends are chamfered to help guide the duct during insertion.

Parameter	Value	Unit
side A internal width	225	mm
side A internal height	59.5	mm
sleeve length on side A	20	mm
side B internal width	114.5	mm
side B internal height	95	mm
sleeve length on side B	20	mm
thickness	1	mm
transition length	20	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	inside

Rectangular tube adapter STL 3D file 225x59.5 mm to 114.5x95 mm – transition: 20 mm (📦 #9466)

1 object(s) - format STL

Rectangular adapter exported as STL 3D file. Side A offers an internal cross-section of 225x59.5 mm (rectangular) and side B uses 114.5x95 mm (rectangular). The sleeve insertion length is the same on both sides, 10 mm. Between the two sleeves, the transition section adds 20 mm, giving an overall length of 40 mm. Internal chamfers at the ends improve assembly and provide a smoother insertion of the mating duct.

Parameter	Value	Unit
side A internal width	225	mm
side A internal height	59.5	mm
sleeve length on side A	10	mm
side B internal width	114.5	mm
side B internal height	95	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 duct adapter STL 3D file 228x98 mm to 158x63 mm – transition: 20 mm (📦 #9464)

1 object(s) - format STL

Rectangular pipe adapter exported as STL 3D file. Side A uses an internal cross-section of 228x98 mm (rectangular), whereas side B is 158x63 mm (rectangular). The sleeve on side A provides an insertion length of 20 mm, and the sleeve on side B 30 mm. The transition section between the two sides is 20 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	228	mm
side A internal height	98	mm
sleeve length on side A	20	mm
side B internal width	158	mm
side B internal height	63	mm
sleeve length on side B	30	mm
thickness	3	mm
transition length	20	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	inside

Rectangle-to-rectangle duct adapter STL file 220x33 mm to 220x26.5 mm – transition: 20 mm (📦 #9379)

1 object(s) - format STL

Rectangular duct adapter downloadable as STL 3D file. Side A offers an internal cross-section of 220x33 mm (rectangular) and side B uses 220x26.5 mm (rectangular). The insertion length on side A is 25 mm, while on side B it is 24 mm. Between the two sleeves, the transition section adds 20 mm, giving an overall length of 69 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	220	mm
side A internal height	33	mm
sleeve length on side A	25	mm
side B internal width	220	mm
side B internal height	26.5	mm
sleeve length on side B	24	mm
thickness	2	mm
transition length	20	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	outside

Rectangular pipe adapter STL 3D file 243x33 mm to 226.5x25 mm – transition: 20 mm (📦 #9378)

1 object(s) - format STL

Rectangular tube adapter downloadable as STL 3D file. Side A uses an internal cross-section of 243x33 mm (rectangular), whereas side B is 226.5x25 mm (rectangular). The insertion length on side A is 25 mm, while on side B it is 24 mm. Between the two sleeves, the transition section adds 20 mm, giving an overall length of 69 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	243	mm
side A internal height	33	mm
sleeve length on side A	25	mm
side B internal width	226.5	mm
side B internal height	25	mm
sleeve length on side B	24	mm
thickness	2	mm
transition length	20	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	outside

Rectangular duct adapter STL 3D file 243x33 mm to 229x28 mm – transition: 20 mm (📦 #9373)

1 object(s) - format STL

Rectangular duct sleeve downloadable as STL 3D file. Side A uses an internal cross-section of 243x33 mm (rectangular), whereas side B is 229x28 mm (rectangular). The sleeve insertion length is the same on both sides, 25 mm. The transition section between the two sides is 20 mm long, for an overall length of 70 mm (side A sleeve, transition and side B sleeve). The outer edges at the ends are chamfered, which simplifies inserting the adapter into the mating duct.

Parameter	Value	Unit
side A internal width	243	mm
side A internal height	33	mm
sleeve length on side A	25	mm
side B internal width	229	mm
side B internal height	28	mm
sleeve length on side B	25	mm
thickness	3	mm
transition length	20	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	outside

Rectangular tube adapter STL file 243x33 mm to 234x30 mm – transition: 20 mm (📦 #9372)

1 object(s) - format STL

Rectangular duct fitting exported as STL 3D file. The internal cross-section on side A is 243x33 mm (rectangular), while side B is 234x30 mm (rectangular). The sleeve insertion length is the same on both sides, 25 mm. Between the two sleeves, the transition section adds 20 mm, giving an overall length of 70 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	243	mm
side A internal height	33	mm
sleeve length on side A	25	mm
side B internal width	234	mm
side B internal height	30	mm
sleeve length on side B	25	mm
thickness	3	mm
transition length	20	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	outside

Rectangular tube adapter STL 3D file 243x33 mm to 234x30 mm – transition: 20 mm (📦 #9371)

1 object(s) - format STL

3D STL file for rectangular adapter. Side A offers an internal cross-section of 243x33 mm (rectangular) and side B uses 234x30 mm (rectangular). On side A, the sleeve length is 25 mm, and on side B it is 26.5 mm. The transition section runs for 20 mm and the overall length is 71.5 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	243	mm
side A internal height	33	mm
sleeve length on side A	25	mm
side B internal width	234	mm
side B internal height	30	mm
sleeve length on side B	26.5	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 196x146 mm to 180x104 mm – transition: 20 mm (📦 #9335)

1 object(s) - format STL

Rectangular duct fitting exported as STL 3D file. The internal cross-section on side A is 196x146 mm (rectangular), while side B is 180x104 mm (rectangular). The insertion length on side A is 5 mm, while on side B it is 15 mm. The transition section runs for 20 mm and the overall length is 40 mm, sleeves included. No chamfers are applied at the ends; both inner and outer edges remain sharp.

Parameter	Value	Unit
side A internal width	196	mm
side A internal height	146	mm
sleeve length on side A	5	mm
side B internal width	180	mm
side B internal height	104	mm
sleeve length on side B	15	mm
thickness	2	mm
transition length	20	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	none

Rectangle-to-rectangle duct adapter STL 3D file 200x150 mm to 180x100.4 mm – transition: 20 mm (📦 #9333)

1 object(s) - format STL

Rectangular duct fitting downloadable as STL 3D file. Side A uses an internal cross-section of 200x150 mm (rectangular), whereas side B is 180x100.4 mm (rectangular). The sleeve on side A provides an insertion length of 5 mm, and the sleeve on side B 20 mm. Between the two sleeves, the transition section adds 20 mm, giving an overall length of 45 mm. Internal chamfers are added at the ends to make assembly and duct insertion easier.

Parameter	Value	Unit
side A internal width	200	mm
side A internal height	150	mm
sleeve length on side A	5	mm
side B internal width	180	mm
side B internal height	100.4	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

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

1 object(s) - format STL

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 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

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

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 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

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

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.