Valterra R920BK Telescopic Gravity Fresh Water Fill / Inlet BlackMost trailers have a gravity fill inlet which allows you to fill the fresh water tank by loosely fitting the water hose to the fill inlet. Water should be turned on at a slow flow rate, allowing gravity to pull the water through the fill hose and into the fresh water tank. This gravity water inlet has a tank vent connection. This is a retro style telescopic RV gravity fill inlet for your fresh water system. The inlet size is 1-3/8″ x 1-1/4″ with a barbed fitting to connect your supply hose. Made of a durable black plastic. Constructed with a built-in check valve.Specs:Cut Hole Size:2 5/8″Faceplate:3 1/2″ X 3 1/2″Faceplate C/Hole to C/Hole (L&W not Diagonal):2 1/2″