The Zodiac Baracuda W60050 Flowkeepr Valve is used with Baracuda G3 pool cleaners and is designed to regulate the rate of flow so that the pool pump and the G3 cleaner run properly. Pool pumps provide more gallon per minute flow than the G3 cleaner requires and the self adjusting flowkeeper valve provides a by-pass. The flowkeeper valve must be used in single skimmer pools for the G3 cleaner to run properly.