This Jobe Valves Topaz Part Fill Valve is intended for use in rain water harvesting tanks. The purpose of the float valve is to automatically maintain a low level of water in the tank during periods of no or low rainfall. This allows services fed by the tank to continue while leaving capacity in the tank for refilling by the next rain. The part fill valve's float ball is adjustable and can mount in multiple positions for just the right water level. The high-flow valve detaches from its base with a simple 1/4 turn for easy cleaning or servicing.