Hydrotools 71601 Model 71601 Replacement 6-Way Valve for Sand Filter Systems - This is a replacement sand filter valve for Hydrotools sand filter systems with 16", 19", 22" and 24" sand filters and sand filter systems. It is for use with Hydrotools model 71610, 71915, 72220 and 72420 sand filter systems and model 71600, 71900, 72200 and 72400 sand filters. Includes Filter, Backwash, Rinse, Waste, Recirculate and Closed operation selections.