The Duct Increaser/Reducer connects 3 in. - 4 in. ducts together. It is ideal for bathroom fan exhaust applications. Product width is 4 in. Made of polypropylene Used when your exhaust port or exhaust hood needs to be increased from 3 in. to accommodate a 4 in. duct Consult your local building codes for approved installation practices Lightweight design Dimensions Product Depth (in.) 4 Product Height (in.) 3.38 Product Width (in.) 4 Details Brand/Model Compatibility All HVAC application Ventilation Material Polypropylene Pack Size 15 Product Weight (lb.) 0.112