Double action pump features twin diaphragms to ensure continuous operation if one is damaged, nitrile valves and diaphragms, and powder coated diecast aluminum alloy construction. Can pump oily bilge water, effluent, and diesel. No tools required for inspection and cleaning. Pump may be accepted on some vessels for use as an emergency fire pump. Takes 1-1/2" hose. GPM 31 Description On Deck mount