905083 (Febco) | 2-1/2 - 10 Inch | 825Y RP Metal Air Gap Drain | Npt ThreadThis 2 1 2 to 10 Inch Metal Air Gap Drain is Installed Under a Reduced Pressure Assembly, Series 825YD, to Catch Minor Relief Valve Discharge Due to Pressure Fluctuations And Or Minor Check Valve Fouling. This Drain Reduces The Amount of Water Splashing in The Area Around Reduced Pressure Assemblies While Funneling Relief Valve Discharge Into The Drain. Febco 905083