This is the generic version of the Polaris G52 Back-up Valve Assembly. This is a CMP replacement back up valve. It has a timer mechanism inside that diverts water out of the side jet every 5-10 minutes. This jet acts as a back up, pulling the cleaner out from the pool floor or wall. There is an arrow on one side of the hose barb that should face towards the cleaner. It is designed to go inline on the hose 5-6 feet back from the head of the unit.This backup valve includes two hose nuts in the package.