Designed to allow soft rubber washer hose or washer metal drain hook to share standpipe with Air Gap unitFits 1 1/2" or 2" standpipes. Unit housing length approx. 5 1/2" (13.97cm). Recommended usage 1 to 7 G.P.M.(3.7 to 26.5 Liters/minute) Tested at 15 G.P.M(56.8 Liters/minute) in lab tests. Designed to allow soft rubber washer hose or washer metal drain hook to share standpipe with Air Gap unit. Inlet port fits 1/2" sch 40 PVC slip fittings or our special couplings (P/N 211217) or (P/N 211213S) or (P/N 51024) or (P/N 8504).Provides more than twice the code required minimum air gap opening.