Cartridge Bilge Pump, Cartridge Combo, with automatic operation from the electro-magnetic float switch. The Cartridge Combo 750 GPH pumps are equipped with easy-to-install Dura-Port discharge ports to eliminate stress cracking caused by overtightened hose clamps. The pumps include both a straight and a 90° smooth elbow Dura-Port as well as a removable check valve.