The Valterra RV Freshwater Inlet is a standard city water inlet. It's made with a durable plastic flange and brass fitting so it won't rust. It accepts a garden hose fitting and connects to your water system with a standard brass 1/2" male pipe thread. It has an integrated check valve for back flow prevention. The flange has a diameter of 2-13/16".SpecsInlet: 1/2" MPTFlange: 2-13/16" O.D. Cutout: 1-1/8" dia. Flange Material: Black Plastic Standard 1/2"" male pipe thread Integrated check valve for back flow prevention Flange measures 2-13/16"" O.D. | Valterra A01-0169LF RV Freshwater Inlet, Black Flange