The RuleMate Bilge Pump provides ultimate pumping performance to help keep your bilge clear of nuisance water. This bilge pump operates using an internal level sensor. When water reaches 2", the pump automatically activates, removing water from the bilge. When the water level reaches 3/8", the pump turns off until the water level rises again. If the level sensor becomes fouled by debris or contaminated water, a unique back up feature will prevent the pump from entering a run-on condition, protecting the battery while maintaining automatic operation. New Design FeaturesHigher Flow â Optimized impeller provides up to 10% more flow at the same amperage. Auto Sense Intelligence â Integral water level sensor controls the pump automatically. Back Up Feature â Prevents continuous running. If sensor is fouled by debris, pump reverts to 2.5 minute cycle mode. Smaller Footprint â This new model is 2/3 the size of previous models. Built-In Thermal Cut-Off (TCO) â Provides added protection for pump and vessel. Back Flow Prevention âReduces the amount of water left over in the bilge, reducing odor and helping keep your bilge cleaner. Hidden Air Vents In The Body â Helps prevent air locking in challenging plumbing installations and helps with the check valve. Threaded Discharge â Easier installation and maintenance. SpecificationsModel No.: RM500BNominal GPH: 500Volts: 12 DCAmps @ 12V: 1.8Amps @ 13.6V: 2.4Check Valve: YesHose Dia.: 3/4"Dimensions: 2.85"W x 4.38"H x 3.95"L (5.08"L including fitting) Built-in thermal cutoff adds protection Back Up Feature prevents continuous running if fouled by debris Smaller footprint | 500 GPH Automatic Submersible Bilge Pump