Air gap provides full backflow and backsiphonage backflow protection for a variety of applications. It fits in 1-1/2 inch and 2 inch standpipes and the inlet accommodates inch schedule 40 PVC fittings. Designed to allow rubber or metal waste hoses to share a standpipe with the air gap. Can be used with home water filtration units and dehumidifiers.Provides full backflow and backsiphonage backflow protection,Designed to allow soft rubber washer hose or aluminum washer drain hook up to share stand pipe,For use with washing machine discharge, dehumidifiers, water filtration devices, and water softeners.,Fits 1-1/2 and 2 metal or plastic standpipes,Plastic