The valve is configured for above or below water mounting. The float operates a small pilot valve which in turn operates the main diaphragm valve. Topaz trough valves are a good choice where their high flow, compact, robust, non corrosive construction and high level of adaptability are needed. Features: Ideal for use with all makes and models of rain water harvesting tanks Compact Constructed from non corroding materials Valve can be locked in off position using the lock off switch Up to 150mm differential obtainable (dependant on pressure) Detach Valve Seal Access System for quick access to valve seal