Rule 25SA Bilge pump, AUTOMATIC WATER SENSING. 3/4" outlet, 12 volt. 500 gallons per hour. Automatically removes water from engine compartment; cycles every 20 seconds to check for water. Features exclusive Rule moisture tight seals. Compact, efficient, maintenance-free positive snap lock strainer base. Totally submersible, silent running, vibration less, ignition protected, water-cooled motor. Anti-airlock features, no burnout when run dry. Built-in thermal cut-off (TCO) provides added protection for the pump and vessel. Stainless steel shaft.