the Whale Supersub features a low profile design for narrow bilges. Pump can be installed in a horizontal or vertical outlet position, and on horizontal or vertical surfaces. The removable strainer and twist lock assembly and disassembly, makes cleaning the pump simple and easy. A 3/4 inch non return valve fitted in the line stops water from flowing back into the bilge. The Supersub has very low power consumption and available in 500 and 650 GPH (gallons per hour) versions.