The Rule Mate RM500B automatic submersible bilge pump eliminates the need for a separate float switch to activate the pump. Once power is supplied to the bilge pump, the pump will activate once the water reaches 2" (5cm), once the water reaches 3/8" (0.9cm) the pump will turn off until the water hits 2" again. The Rule Mate bilge pump is 2/3 of the size of the old models creating a smaller footprint, this new model also has a built in thermal cut-off to add extra protection for the pump and vessel. The Rule Mate 500B submersible bilge pump is recommended for discharge heads up to a maximum of 3 metres. The submersible bilge pump meets ISO8846 marine (ignition) and ISO8849 marine (bilge pump) standards. Rule Mate pumps feature a backup device that knows if the electronic bilge switch becomes covered by oil, grease and debris, by checking for water resistance against the impeller. If no water is present the pump will revert to an auto-timed mode, where the pump cycles every 2.5 minutes to check for water, until the sensor has been cleaned. Once the switch is cleaned the pump will revert back to the level sensing mode. Includes Check Valve and a 60cm wire. Suitable for 24 Volt systems.