4" to 3" Inch Duct Reducer Round Reducer Duct Fitting Pipe Increaser Reducer Made from Galvanized Steel (Drain, Waste and Vent) Reducing Coupling (Metal, 4 to 3 Inch)

$5.19

AC Infinity Duct Adapter, 6” to 4” Ducting Reducer Increaser Cone for Grow Tent Bathroom Kitchen Ventilation Systems

$7.99

HVAC OV 5" to 4" Inch Round Duct Reducer - Galvanized Steel Pipe Increaser - Coupling for Round Duct Ventilation Systems - Heating & Cooling, HVAC

$24.99

HVAC OV 4" to 3" Inch Round Duct Reducer - Galvanized Steel Pipe Increaser - Coupling for Round Duct Ventilation Systems - Heating & Cooling, HVAC

$98.15

Vent Systems 4'' Inch Galvanized Steel Duct Connector - Round Ventilation Duct Extension - Metal Vent Coupler - Metal Hose Coupling - Galvanised Pipe Connector

$9.99

Elifecenter Universal Stainless ID 4 inch Exhaust Adapter Reducer fit for Pipe Connection, Whole Length 4 Inch

$34.99

5.9 inch/6 inch Portable Air Conditioner Exhaust Hose Coupler Window Adapter A/C Unit Tube Connector Mobile air Conditioning Accessories Square to Round

$5.95

Exhaust Pipe/Muffler Adapter Reducer Sleeve Adapters (1.5", 1-5/8", 1.75")

$13.99

Vent Systems 4" inch Air Vent Duct Connector Flange Straight Ventilation Pipe Plastic Ducting Connector Plate for Cooling Heating Ventilation System HVAC 4" inch - Pack of (1)

$9.9

VIVOSUN 6 Inch Inline Duct Fan 240 CFM, HVAC Exhaust Ventilation Fan with Low Noise for Basements, Bathrooms, Kitchens and Attics, Silver

$139.99

LEAK FREE 6"-4" Reducer Adapter for 6" AC Infinity Inline Fan S6/T6 (2 Pack)

$17.96

Hon&Guan 3 Inch Duct Connector, Plastic Duct Flange Vent Systems 3 Flange for Heating Cooling Ventilation Vent System-2PCS.

$7.99

VIVOSUN 4 Inch Inline Duct Fan 100 CFM, HVAC Exhaust Ventilation Fan with Low Noise for Basements, Bathrooms, Kitchens and Attics, Silver

$99

2 PCS Universal 2.75" ID to 3" OD Exhaust Pipe Adapter Connector Reducer 304 Stainless Steel 2.75 Inch to 3 Inch 2 3/4” ID to 3” OD kit

$27.99

Broan BROAN-639-BLACK Black 639 Wall Cap for 3-1/4" x 10" Duct for Range Hoods and Bath Ventilation Fans

$68.86

AC Infinity Noise Reduction Clamp 6-Inch, Duct Coupler with Stainless Steel Clamps, Flexible Rubber Coupling for Inline Fans and Carbon Filters in Growing and HVAC

$9.98

Metalwork 304 Stainless Steel Pipe Fitting Reducing Adapter 1/2" NPT Female x 1/4" NPT Male Reducer Connector 2000psi (1 Pc)

$31.99

Universal ID 2.5" to ID 2.5" Stainless Steel Exhaust Reducer Adapter Coupler Pipe (2 1/2" X 3.6")

$9.99

iPower 6 inch Inline Booster Fan and 16 Feet Non-Insulated Flex Air Aluminum Ducting Vent Hose for Kitchen Bathroom Grow Tent HVAC Exhaust or Intake

$20.62

Metalwork Stainless Steel 304 Pipe Fitting Reducing Adapter 1/2" NPT Female x 3/8" NPT Male Reducer Connector 2000psi (1 Pcs)

$13.99

Mudder 7 Pieces Air Conditioning Refrigerant Angled Compact Ball Valve 1/4 Inch for R410A R134A R12 R22 HVAC and R410A Adapter 5/16 Inch Female to 1/4 Inch Male Flare for Mini Split System

$39.99

HG Power 6 Inch Air Vent Covers, ABS Adjustable Soffit Vent, Round Ceiling Diffuser for Living Room, Closet, Bathroom, Kitchen, Ventilation Use, White

$59.99

Manual D - Residential Duct Systems

$56.99

Hon&Guan Duct Connector Flange 6 Inch, Plastic 6 Inch Dust Collection Fittings Dryer Vent Connector Flange For Heating Cooling Ventilation System, Black.

$11.99

AC Infinity RAXIAL S6, Inline Booster Duct Fan 6” with Speed Controller - Low Noise Inline HVAC Blower Can Fan for Basements, Bathrooms, Kitchens, Workshops

$59.99

BATONECO Exhaust Pipe to Component Pipe Adapter Reducer Kits 3 Inch ID 2.5 Inch OD Universal Stainless Steel 3'' to 2.5''

$18.69

A-KARCK Exhaust Adapter Connector 3" OD to 3.5" OD, Exhaust Pipe Reducer 4" Overall Length 304 Stainless Steel

$21.99

Metalwork Stainless Steel 304 Forged Pipe Fitting Reducing Adapter 3/8" NPT Female x 1/4" NPT Male Reducer Connector 2000psi (1 Pc)

$19.99

A-KARCK Exhaust Adapter Connector 3.5" OD to 4" OD, Exhaust Pipe Reducer 4" Overall Length 304 Stainless Steel

$13.99

COSMO COS-5MU36 Under Cabinet Range Hood Ductless Convertible Duct, Slim Kitchen Stove Vent with, 3 Speed Exhaust Fan, Reusable Filter and LED Lights in Stainless Steel (36 inch)

$378.01

HealSmart Dryer Vent Hose 4 inch 8 feet Flexible Aluminum Foil Ducting with 2 Clamps for HVAC Ventilation, Non-Insulated, Silver

$11.99

Universal ID 2 Inch to OD 3 Inch Exhaust Adapter, Stainless Steel Exhaust Coupler(2" ID to 3" OD), Adapter Reducer Whole Length 3.6 Inch

$28.88

Broan-NuTone 636 Steel Roof Vent Cap for 3" and 4" Round Duct, For Bathroom Ventilation Fans, Black

$9.97

6 Inch Round Air Vent, HG Power 2-Pack ABS Louver Grille Cover Soffit Vent with Built-in Screen Mesh for Bathroom Office Kitchen Ventilation White - Opening Size 5.66"

$9.99

AC Infinity 6" Backdraft Damper, One-Way Airflow Ducting Insert with Spring-Loaded Folding Blades for 6” Ducting in Range Hoods and Bathrooms Fans

$18.99

Drasum Dryer Vent Hose Easy-to-Install 4 Inch Duct 6.56-Feet Heavy-Duty Duct with 2 Clamps – 4 Layer PVC and Aluminum Flexible Duct for Heating Cooling Ventilation and Exhaust

$14.99

Universal 2.5" ID to 3" OD Exhaust Pipe Adapter Connector Reducer 304 Stainless Steel 2.5 Inch to 3.0 Inch 2 1/2” ID to 3.0” OD kit-2PCS

$79.65

Rubber-Cal "HVAC Insulated-Flex" Ducting Ventilation Duct Hose, 4-Inch by 25-Feet

$8.95

Universal 2.25" ID to 3" OD Exhaust Pipe Adapter Connector Reducer 304 Stainless Steel 2.25 Inch to 3.0 Inch 2 1/4” ID to 3.0” OD kit

$43.9

iPower 4 Inch 100 CFM Inline Duct Fan with Low Noise, Exhaust Booster for HVAC Ventilation in Grow Tent, Basements, Bathrooms and Kitchens, Grey

$66.89

VIVOHOME 4 Inch 25 Feet Aluminum Flexible Dryer Vent Hose Air Ducting Non-Insulated with 2 Stainless Steel Clamps for HVAC Ventilation and Exhaust Pack of 1

$9.97

HG Power 6 Inch Round Air Vent, ABS Louver Grille Cover with Built-in Screen Mesh, White Soffit Vent for Bathroom Office Kitchen Ventilation - Opening Size 5.66"

$53.99

Metalwork Stainless Steel 304 Forged Pipe Fitting Reducing Adapter 1/4" NPT Female to 1/8" NPT Male Reducer Connector 2000psi (1pc)

$52.99

Transition Reducer, 2.5in to 3in Stainless Steel Tubing Transition Adapter Reducer Pipe Connector

$35.59

4" Inch Duct Connector Flange - Plastic Straight Pipe Flange for Heating Cooling - Inlet Outlet Ventilation System - Ducting Coupling Wall Plate - Assembly Joint (100mm)

$18.99

Hon&Guan 6'' Soffit Vent Exhaust Vent, 6 Inch Round Air Vent Dryer Vent Soffit with Built-in a Fly Screen for Bathroom Office Home(150mm）

$8.95

Dryer Vent Hose Flexible Aluminum Foil PVC Air Ducting for HVAC Ventilation Fan Filter Kitchens Exhaust,White (4IN 8FT)

$9.97

Universal 2.75" ID to 3" OD Exhaust Pipe Adapter Connector Reducer 304 Stainless Steel 2.75 Inch to 3 Inch 2 3/4” ID to 3” OD kit

$94.99

AC Infinity 4" Backdraft Damper, One-Way Airflow Ducting Insert with Spring-Loaded Folding Blades for 4” Ducting in Range Hoods and Bathrooms Fans

$9.99

Hon&Guan 5 inch Air Duct - 16 FT Long, Black Flexible Ducting HVAC Ventilation Air Hose for Grow Tents, Dryer Rooms,Kitchen

$41.99

Broan-Nutone 682 Duct-Free Ventilation Fan, White Square Ceiling or Wall Exhaust Fan with Plastic Grille

$111.84

Angled Reducer 4” to 2-1/2”, Connect Shop Vac to Dust Collection Port (4in to 2.5in), Adapter Converter, 45-Degree Elbow, Attach Woodworking Dust Chute to Vacuum Hose, R4520 R4512 (4" to 2-1/2")

$14.99

Air Vent Extender for Under Furniture, Floor Vent Deflector for Floor Register Up to 12" Wide, Extends from 17"-33" (1PCS)

$16.99

Quickun Plastic Exhaust Air Silencer, 1/4" Air Line Pneumatic Muffler Black Air Compressor Fitting (Pack of 5)

$56.99

RP Remarkable Power, RK7550-3" x 6" Heavy Duty Stainless Steel Exhaust Flex Pipe 10" OL

$18.69

Quickun Plastic Exhaust Air Silencer, 3/8" Air Line Pneumatic Muffler Black Air Compressor Fitting (Pack of 5)

$6.99

Broan-NuTone Available NuTone WVK2A Flexible Wall Ducting Kit for Ventilation Fans, 4-Inch

$21.97

VENTISOL 24 Inch Industrial Floor Drum Fan, 8600 CFM Heavy Duty Floor Fan 3-Speed Air Circulator with Castors, High Velocity Commercial Shop Fan for Warehouse, Basement, Facotry, Barn, Garage

$46.5

Piutouyar 20Pcs 53mm/2" Air Vents Round Soffit Vents, Stainless Steel Circular Soffit Vent Mesh Hole Louver for Kitchen, Bathroom, Cabinet and Wardrobe (Black)

$25.99

Ruibapa R410a Adapter 5/16-inch SAE Female to 1/4-inch SAE Male Flare for Air Conditioners HVAC Refrigeration,2 Straight Adapter+2 Angled Adapter P-055-kit

$12.99