Rule have totally re-engineered their Rule Mate Automatic Bilge Pumps range and now provide some of the most technically advanced and reliable automatic pumps on the market The Rule Mate 500 bilge pump operates using an internal level sensor. When water reaches 2" (5cm), the pump will automatically activate, removing water from Bilge. When the water level reaches 3/8" (0.9cm) the pump will turn off until the water level rises again. Bilges are not always clean and free from debris. If the level sensor becomes fouled by debris or contaminated water, Rule Mate’s unique back up feature will prevent the pump from entering a run-on condition, protecting the battery while maintaining automatic operation. Features Fully automated bilge pump with integral sensor. Back up feature to prevent dry running if sensor is fouled, pump reverts to 2.5 minute cycle mode. Compact pump for smaller vessels. Tough plastic body. Back flow prevention to reduce the amount of water left over in the bilge, Air Vents in the body to help prevent air locks in challenging installations. Quick release inlet strainer allows rapid cleaning. Low amp draw conserves batteries. Ignition protected and built in thermal cut-off. Specification Voltage: 12volt Amps @ 13.6V: 2.4amp Amps @ 12v: 1.8 amp Fuse Size: 4(amp) Connections: For 19mm (3/4") or 25mm (1") bore hose on inlet and outlet. Straight or 90º Elbow Output: Up to 31 litres/minute (7 gallons/minute) Discharge head:Max. recommended discharge head 2m Wiring : 3 Wire System – Requires On-Off-Auto Panel Switch to compete install  Dimensions Dimensions: 112mm high, 130mm long, 73mm wide.