Rectangular-to-rectangular duct adapter 3D models

First model: 2025-11-25

Number of 3D models generated: 208

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 112x112 mm to 112x56 mm – transition: 52 mm (📦 #12629)

1 object(s) - format STL

Rectangular duct fitting exported as STL 3D file. Side A offers an internal cross-section of 112x112 mm (square) and side B uses 112x56 mm (rectangular). The insertion length on side A is 25 mm, while on side B it is 30 mm. The transition section between the two sides is 52 mm long, for an overall length of 107 mm (side A sleeve, transition and side B sleeve). The ends are left without chamfers, with sharp inner and outer edges. Side B is offset by 26 mm along the Z axis relative to side A.

Parameter	Value	Unit
side A internal width	112	mm
side A internal height	112	mm
sleeve length on side A	25	mm
side B internal width	112	mm
side B internal height	56	mm
sleeve length on side B	30	mm
thickness	2	mm
transition length	52	mm
Y offset	0	mm
Z offset	26	mm
end chamfers	none

Rectangular tube adapter STL 3D file 112x112 mm to 112x56 mm – transition: 52 mm (📦 #12627)

1 object(s) - format STL

Rectangular duct connector exported as STL 3D file. The internal cross-section on side A is 112x112 mm (square), while side B is 112x56 mm (rectangular). Each sleeve provides an insertion length of 25 mm. Between the two sleeves, the transition section adds 52 mm, giving an overall length of 102 mm. The ends are left without chamfers, with sharp inner and outer edges. Side B is offset by 26 mm along the Z axis relative to side A.

Parameter	Value	Unit
side A internal width	112	mm
side A internal height	112	mm
sleeve length on side A	25	mm
side B internal width	112	mm
side B internal height	56	mm
sleeve length on side B	25	mm
thickness	2	mm
transition length	52	mm
Y offset	0	mm
Z offset	26	mm
end chamfers	none

Rectangular duct adapter STL 3D file 204x60 mm to 204x60 mm – transition: 100 mm (📦 #12489)

1 object(s) - format STL

Rectangular vent adapter downloadable as STL 3D file. On both side A and side B, the internal cross-section is 204x60 mm, with a rectangular geometry. Both side A and side B sleeves share the same insertion length of 50 mm. The transition section runs for 100 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 30 mm along the Z axis relative to side A.

Parameter	Value	Unit
side A internal width	204	mm
side A internal height	60	mm
sleeve length on side A	50	mm
side B internal width	204	mm
side B internal height	60	mm
sleeve length on side B	50	mm
thickness	2	mm
transition length	100	mm
Y offset	0	mm
Z offset	30	mm
end chamfers	none

Rectangular duct adapter STL 3D file 62x62 mm to 66x62 mm – transition: 35 mm (📦 #12427)

1 object(s) - format STL

3D STL file for rectangular adapter. Side A offers an internal cross-section of 62x62 mm (square) and side B uses 66x62 mm (rectangular). The insertion length on side A is 35 mm, while on side B it is 20 mm. Between the two sleeves, the transition section adds 35 mm, giving an overall length of 90 mm. 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.

Parameter	Value	Unit
side A internal width	62	mm
side A internal height	62	mm
sleeve length on side A	35	mm
side B internal width	66	mm
side B internal height	62	mm
sleeve length on side B	20	mm
thickness	4	mm
transition length	35	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	inside

Rectangular tube adapter STL 3D file 62x62 mm to 65x65 mm – transition: 180 mm (📦 #12424)

1 object(s) - format STL

3D STL file for rectangular duct sleeve. Side A uses an internal cross-section of 62x62 mm (square), whereas side B is 65x65 mm (square). Both side A and side B sleeves share the same insertion length of 10 mm. The transition section between the two sides is 180 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 ends are left without chamfers, with sharp inner and outer edges.

Parameter	Value	Unit
side A internal width	62	mm
side A internal height	62	mm
sleeve length on side A	10	mm
side B internal width	65	mm
side B internal height	65	mm
sleeve length on side B	10	mm
thickness	1	mm
transition length	180	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	none

Rectangular pipe adapter STL file 203x203 mm to 203x203 mm – transition: 85 mm (📦 #12222)

1 object(s) - format STL

Rectangular vent adapter exported as STL 3D file. Side A and side B share the same internal cross-section, 203x203 mm, with a square profile. The sleeve insertion length is the same on both sides, 30 mm. The transition section between the two sides is 85 mm long, for an overall length of 145 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	203	mm
side A internal height	203	mm
sleeve length on side A	30	mm
side B internal width	203	mm
side B internal height	203	mm
sleeve length on side B	30	mm
thickness	3	mm
transition length	85	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	none

Rectangular duct adapter STL file 203.2x203.2 mm to 203.2x203.2 mm – transition: 60 mm (📦 #12208)

1 object(s) - format STL

Rectangular duct adapter exported as STL 3D file. Side A and side B share the same internal cross-section, 203.2x203.2 mm, with a square profile. The sleeve on side A provides an insertion length of 20 mm, and the sleeve on side B 30 mm. Between the two sleeves, the transition section adds 60 mm, giving an overall length of 110 mm. No chamfers are applied at the ends; both inner and outer edges remain sharp.

Parameter	Value	Unit
side A internal width	203.2	mm
side A internal height	203.2	mm
sleeve length on side A	20	mm
side B internal width	203.2	mm
side B internal height	203.2	mm
sleeve length on side B	30	mm
thickness	3	mm
transition length	60	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	none

Rectangular pipe adapter STL 3D file 203x203 mm to 203x203 mm – transition: 55 mm (📦 #12200)

1 object(s) - format STL

Rectangular pipe adapter downloadable as STL 3D file. Both ends have the same internal cross-section, 203x203 mm, with a square shape. The sleeve on side A provides an insertion length of 10 mm, and the sleeve on side B 60 mm. Between the two sleeves, the transition section adds 55 mm, giving an overall length of 125 mm. No chamfers are applied at the ends; both inner and outer edges remain sharp.

Parameter	Value	Unit
side A internal width	203	mm
side A internal height	203	mm
sleeve length on side A	10	mm
side B internal width	203	mm
side B internal height	203	mm
sleeve length on side B	60	mm
thickness	3	mm
transition length	55	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	none

Rectangular duct adapter STL file 168x32 mm to 203x203 mm – transition: 170 mm (📦 #12179)

1 object(s) - format STL

Rectangular duct fitting provided as 3D STL file. Side A uses an internal cross-section of 168x32 mm (rectangular), whereas side B is 203x203 mm (square). Each sleeve provides an insertion length of 20 mm. The transition section between the two sides is 170 mm long, for an overall length of 210 mm (side A sleeve, transition and side B sleeve). Inner and outer edges at both ends are left unchamfered.

Parameter	Value	Unit
side A internal width	168	mm
side A internal height	32	mm
sleeve length on side A	20	mm
side B internal width	203	mm
side B internal height	203	mm
sleeve length on side B	20	mm
thickness	3	mm
transition length	170	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	none

Rectangle-to-rectangle duct adapter STL file 165x31.8 mm to 209x209 mm – transition: 150 mm (📦 #12165)

1 object(s) - format STL

3D STL file for rectangular pipe adapter. Side A uses an internal cross-section of 165x31.8 mm (rectangular), whereas side B is 209x209 mm (square). Both side A and side B sleeves share the same insertion length of 25.4 mm. The transition section runs for 150 mm and the overall length is 200.8 mm, sleeves included. No chamfers are applied at the ends; both inner and outer edges remain sharp.

Parameter	Value	Unit
side A internal width	165	mm
side A internal height	31.8	mm
sleeve length on side A	25.4	mm
side B internal width	209	mm
side B internal height	209	mm
sleeve length on side B	25.4	mm
thickness	3	mm
transition length	150	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	none

Rectangular tube adapter STL file 210.9x210.9 mm to 168x31.7 mm – transition: 100 mm (📦 #12163)

1 object(s) - format STL

Rectangular duct adapter exported as STL 3D file. Side A uses an internal cross-section of 210.9x210.9 mm (square), whereas side B is 168x31.7 mm (rectangular). On side A, the sleeve length is 40 mm, and on side B it is 32 mm. The transition section runs for 100 mm and the overall length is 172 mm, sleeves included. The ends are left without chamfers, with sharp inner and outer edges.

Parameter	Value	Unit
side A internal width	210.9	mm
side A internal height	210.9	mm
sleeve length on side A	40	mm
side B internal width	168	mm
side B internal height	31.7	mm
sleeve length on side B	32	mm
thickness	3	mm
transition length	100	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	none

Rectangle-to-rectangle duct adapter STL file 203.2x203.2 mm to 203.2x203.2 mm – transition: 58 mm (📦 #12120)

1 object(s) - format STL

Rectangular duct sleeve downloadable as STL 3D file. Side A and side B share the same internal cross-section, 203.2x203.2 mm, with a square profile. On side A, the sleeve length is 10 mm, and on side B it is 85 mm. The transition section runs for 58 mm and the overall length is 153 mm, sleeves included. Inner and outer edges at both ends are left unchamfered.

Parameter	Value	Unit
side A internal width	203.2	mm
side A internal height	203.2	mm
sleeve length on side A	10	mm
side B internal width	203.2	mm
side B internal height	203.2	mm
sleeve length on side B	85	mm
thickness	3	mm
transition length	58	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	none

Rectangular pipe adapter STL 3D file 171x32 mm to 210.2x209.9 mm – transition: 55 mm (📦 #12113)

1 object(s) - format STL

3D STL file for rectangular duct adapter. The internal cross-section on side A is 171x32 mm (rectangular), while side B is 210.2x209.9 mm (rectangular). The insertion length on side A is 50.8 mm, while on side B it is 31.8 mm. The transition section runs for 55 mm and the overall length is 137.6 mm, sleeves included. No chamfers are applied at the ends; both inner and outer edges remain sharp.

Parameter	Value	Unit
side A internal width	171	mm
side A internal height	32	mm
sleeve length on side A	50.8	mm
side B internal width	210.2	mm
side B internal height	209.9	mm
sleeve length on side B	31.8	mm
thickness	3	mm
transition length	55	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	none

Rectangular tube adapter STL file 171x32 mm to 202x202 mm – transition: 55 mm (📦 #12092)

1 object(s) - format STL

3D STL file for rectangular duct sleeve. Side A uses an internal cross-section of 171x32 mm (rectangular), whereas side B is 202x202 mm (square). The insertion length on side A is 50.8 mm, while on side B it is 100 mm. The transition section between the two sides is 55 mm long, for an overall length of 205.8 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	171	mm
side A internal height	32	mm
sleeve length on side A	50.8	mm
side B internal width	202	mm
side B internal height	202	mm
sleeve length on side B	100	mm
thickness	3	mm
transition length	55	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	none

Rectangular tube adapter STL 3D file 171x32 mm to 200x200 mm – transition: 55 mm (📦 #12087)

1 object(s) - format STL

Rectangular duct adapter provided as 3D STL file. Side A offers an internal cross-section of 171x32 mm (rectangular) and side B uses 200x200 mm (square). On side A, the sleeve length is 50.8 mm, and on side B it is 100 mm. The transition section between the two sides is 55 mm long, for an overall length of 205.8 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	171	mm
side A internal height	32	mm
sleeve length on side A	50.8	mm
side B internal width	200	mm
side B internal height	200	mm
sleeve length on side B	100	mm
thickness	3	mm
transition length	55	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	none

Rectangular duct adapter STL 3D file 171x32 mm to 209x209 mm – transition: 55 mm (📦 #12052)

1 object(s) - format STL

Rectangular adapter exported as STL 3D file. Side A offers an internal cross-section of 171x32 mm (rectangular) and side B uses 209x209 mm (square). On side A, the sleeve length is 50.8 mm, and on side B it is 100 mm. The transition section runs for 55 mm and the overall length is 205.8 mm, sleeves included. No chamfers are applied at the ends; both inner and outer edges remain sharp.

Parameter	Value	Unit
side A internal width	171	mm
side A internal height	32	mm
sleeve length on side A	50.8	mm
side B internal width	209	mm
side B internal height	209	mm
sleeve length on side B	100	mm
thickness	3	mm
transition length	55	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	none

Rectangular pipe adapter STL file 190x100 mm to 187.7x97.7 mm – transition: 180 mm (📦 #12016)

1 object(s) - format STL

Rectangular pipe adapter exported as STL 3D file. Side A offers an internal cross-section of 190x100 mm (rectangular) and side B uses 187.7x97.7 mm (rectangular). The sleeve insertion length is the same on both sides, 30 mm. The transition section runs for 180 mm and the overall length is 240 mm, sleeves included. Internal chamfers are added at the ends to make assembly and duct insertion easier.

Parameter	Value	Unit
side A internal width	190	mm
side A internal height	100	mm
sleeve length on side A	30	mm
side B internal width	187.7	mm
side B internal height	97.7	mm
sleeve length on side B	30	mm
thickness	2	mm
transition length	180	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	inside

Rectangular duct adapter STL file 190x100 mm to 186.7x96.7 mm – transition: 190 mm (📦 #12015)

1 object(s) - format STL

Rectangular duct sleeve exported as STL 3D file. Side A offers an internal cross-section of 190x100 mm (rectangular) and side B uses 186.7x96.7 mm (rectangular). The sleeve insertion length is the same on both sides, 30 mm. Between the two sleeves, the transition section adds 190 mm, giving an overall length of 250 mm. Internal chamfers are added at the ends to make assembly and duct insertion easier.

Parameter	Value	Unit
side A internal width	190	mm
side A internal height	100	mm
sleeve length on side A	30	mm
side B internal width	186.7	mm
side B internal height	96.7	mm
sleeve length on side B	30	mm
thickness	3	mm
transition length	190	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	inside

Rectangular tube adapter STL file 38.5x180 mm to 38.5x180 mm – transition: 100 mm (📦 #11944)

1 object(s) - format STL

Rectangular tube adapter exported as STL 3D file. Both ends have the same internal cross-section, 38.5x180 mm, with a rectangular shape. The insertion length on side A is 98 mm, while on side B it is 5 mm. The transition section runs for 100 mm and the overall length is 203 mm, sleeves included. Inner and outer edges at both ends are left unchamfered.

Parameter	Value	Unit
side A internal width	38.5	mm
side A internal height	180	mm
sleeve length on side A	98	mm
side B internal width	38.5	mm
side B internal height	180	mm
sleeve length on side B	5	mm
thickness	3	mm
transition length	100	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	none

Rectangle-to-rectangle duct adapter STL 3D file 38.5x177 mm to 38.5x177 mm – transition: 100 mm (📦 #11934)

1 object(s) - format STL

Rectangular duct fitting provided as 3D STL file. Side A and side B share the same internal cross-section, 38.5x177 mm, with a rectangular profile. On side A, the sleeve length is 100 mm, and on side B it is 5 mm. The transition section runs for 100 mm and the overall length is 205 mm, sleeves included. The ends are left without chamfers, with sharp inner and outer edges.

Parameter	Value	Unit
side A internal width	38.5	mm
side A internal height	177	mm
sleeve length on side A	100	mm
side B internal width	38.5	mm
side B internal height	177	mm
sleeve length on side B	5	mm
thickness	3	mm
transition length	100	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	none

Rectangular pipe adapter STL file 220x90 mm to 220x90 mm – transition: 30 mm (📦 #11933)

1 object(s) - format STL

3D STL file for rectangular duct sleeve. Side A and side B share the same internal cross-section, 220x90 mm, with a rectangular profile. Both side A and side B sleeves share the same insertion length of 30 mm. Between the two sleeves, the transition section adds 30 mm, giving an overall length of 90 mm. 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	30	mm
side B internal width	220	mm
side B internal height	90	mm
sleeve length on side B	30	mm
thickness	2	mm
transition length	30	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	inside

Rectangular pipe adapter STL file 220x90 mm to 220x90 mm – transition: 120 mm (📦 #11932)

1 object(s) - format STL

Rectangular conduit adapter exported as STL 3D file. On both side A and side B, the internal cross-section is 220x90 mm, with a rectangular geometry. Both side A and side B sleeves share the same insertion length of 50 mm. The transition section between the two sides is 120 mm long, for an overall length of 220 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	220	mm
side A internal height	90	mm
sleeve length on side A	50	mm
side B internal width	220	mm
side B internal height	90	mm
sleeve length on side B	50	mm
thickness	3	mm
transition length	120	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	none

Rectangular pipe adapter STL file 38x177 mm to 38x177 mm – transition: 20 mm (📦 #11924)

1 object(s) - format STL

Rectangular adapter exported as STL 3D file. Both ends have the same internal cross-section, 38x177 mm, with a rectangular shape. The sleeve on side A provides an insertion length of 10 mm, and the sleeve on side B 5 mm. Between the two sleeves, the transition section adds 20 mm, giving an overall length of 35 mm. The ends are left without chamfers, with sharp inner and outer edges.

Parameter	Value	Unit
side A internal width	38	mm
side A internal height	177	mm
sleeve length on side A	10	mm
side B internal width	38	mm
side B internal height	177	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	none

Rectangular duct adapter STL file 37.5x178 mm to 36x178 mm – transition: 20 mm (📦 #11923)

1 object(s) - format STL

3D STL file for rectangular duct sleeve. The internal cross-section on side A is 37.5x178 mm (rectangular), while side B is 36x178 mm (rectangular). On side A, the sleeve length is 10 mm, and on side B it is 5 mm. The transition section between the two sides is 20 mm long, for an overall length of 35 mm (side A sleeve, transition and side B sleeve). Inner and outer edges at both ends are left unchamfered.

Parameter	Value	Unit
side A internal width	37.5	mm
side A internal height	178	mm
sleeve length on side A	10	mm
side B internal width	36	mm
side B internal height	178	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	none

Rectangular duct adapter STL 3D file 38.5x187.5 mm to 36x187.5 mm – transition: 20 mm (📦 #11922)

1 object(s) - format STL

3D STL file for rectangular duct fitting. Side A uses an internal cross-section of 38.5x187.5 mm (rectangular), whereas side B is 36x187.5 mm (rectangular). The sleeve on side A provides an insertion length of 10 mm, and the sleeve on side B 5 mm. The transition section runs for 20 mm and the overall length is 35 mm, sleeves included. The ends are left without chamfers, with sharp inner and outer edges.

Parameter	Value	Unit
side A internal width	38.5	mm
side A internal height	187.5	mm
sleeve length on side A	10	mm
side B internal width	36	mm
side B internal height	187.5	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	none

Rectangular pipe adapter STL 3D file 151x81 mm to 151x81 mm – transition: 150 mm (📦 #11869)

1 object(s) - format STL

Rectangular duct fitting exported as STL 3D file. On both side A and side B, the internal cross-section is 151x81 mm, with a rectangular geometry. Both side A and side B sleeves share the same insertion length of 40 mm. The transition section runs for 150 mm and the overall length is 230 mm, sleeves included. Internal chamfers are added at the ends to make assembly and duct insertion easier. Relative to side A, side B is shifted by 40 mm along the Y axis and 40 mm along the Z axis.

Parameter	Value	Unit
side A internal width	151	mm
side A internal height	81	mm
sleeve length on side A	40	mm
side B internal width	151	mm
side B internal height	81	mm
sleeve length on side B	40	mm
thickness	2	mm
transition length	150	mm
Y offset	40	mm
Z offset	40	mm
end chamfers	inside

Rectangle-to-rectangle duct adapter STL 3D file 160x110 mm to 107x260 mm – transition: 300 mm (📦 #11726)

1 object(s) - format STL

3D STL file for rectangular tube adapter. The internal cross-section on side A is 160x110 mm (rectangular), while side B is 107x260 mm (rectangular). The insertion length on side A is 20 mm, while on side B it is 100 mm. The transition section between the two sides is 300 mm long, for an overall length of 420 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	160	mm
side A internal height	110	mm
sleeve length on side A	20	mm
side B internal width	107	mm
side B internal height	260	mm
sleeve length on side B	100	mm
thickness	2	mm
transition length	300	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	inside

Rectangular duct adapter STL 3D file 300x100 mm to 300x180 mm – transition: 50 mm (📦 #11491)

1 object(s) - format STL

Rectangular duct transition exported as STL 3D file. The internal cross-section on side A is 300x100 mm (rectangular), while side B is 300x180 mm (rectangular). The sleeve on side A provides an insertion length of 100 mm, and the sleeve on side B 20 mm. The transition section between the two sides is 50 mm long, for an overall length of 170 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	300	mm
side A internal height	100	mm
sleeve length on side A	100	mm
side B internal width	300	mm
side B internal height	180	mm
sleeve length on side B	20	mm
thickness	2	mm
transition length	50	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	inside

Rectangle-to-rectangle duct adapter STL 3D file 39.5x29 mm to 39.5x29 mm – transition: 20 mm (📦 #11394)

1 object(s) - format STL

Rectangular vent adapter downloadable as STL 3D file. On both side A and side B, the internal cross-section is 39.5x29 mm, with a rectangular geometry. The sleeve on side A provides an insertion length of 15 mm, and the sleeve on side B 10 mm. The transition section between the two sides is 20 mm long, for an overall length of 45 mm (side A sleeve, transition and side B sleeve). The shell is very thick, with 6 mm wall thickness. Internal chamfers are added at the ends to make assembly and duct insertion easier.

Parameter	Value	Unit
side A internal width	39.5	mm
side A internal height	29	mm
sleeve length on side A	15	mm
side B internal width	39.5	mm
side B internal height	29	mm
sleeve length on side B	10	mm
thickness	6	mm
transition length	20	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	inside

Rectangular tube adapter STL file 110x55 mm to 110x55 mm – transition: 20 mm (📦 #11361)

1 object(s) - format STL

Rectangular duct adapter exported as STL 3D file. Both ends have the same internal cross-section, 110x55 mm, with a rectangular shape. The sleeve on side A provides an insertion length of 30 mm, and the sleeve on side B 50 mm. The transition section between the two sides is 20 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	110	mm
side A internal height	55	mm
sleeve length on side A	30	mm
side B internal width	110	mm
side B internal height	55	mm
sleeve length on side B	50	mm
thickness	2	mm
transition length	20	mm
Y offset	0	mm
Z offset	0	mm
end chamfers	inside

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.