Review on Peterson Molding 18958CW Drain Valve: Efficient Solution for Quick and Easy Water Management by Wayne Espinoza

This is ONLY for 1/2 inch ID tubing. I thought that would mean it would fit a 3/8" ID hose, but I was wrong. If you don't know your hose size, run the hose in your RV until you see black letters on the See hose. Hose. This letter indicates the size of the hose, both inside and outside diameter. Buy your product accordingly. If it's a 3/8" ID, look elsewhere (eg (Camco 222223, available from Revain).