Camco's Dual Flush Pro allows you to easily rinse and clean out your RV waste tanks and RV sewer hose. This product fits most RV drain outlets and is ideal for RVs without a built-in tank flush. To use, simply connect the Dual Flush Pro to your RV's drain outlet and connect your RV sewer hose outlet to the opposite end. Attach your grey water hose to the backflow stopper. Once connected, reverse flushing forces water back up into the plumbing lines and breaks up pipe clogs. Keep the gate valve closed to prevent waste from flowing from the tanks until your black and grey water tanks are done rinsing. The clear, breakproof polycarbonate adapter lets you see when your tanks are flushed. Open the gate valve to backfill your RV sewer hose with water for thorough rinsing. Patented.