Jabsco-Rule 500 GPH Auto 12V Bilge Pump 25SA The Rule 500 GPH Automatic Bilge Pump provides the ultimate pumping performance, which helps keep your bilge clear of nuisance water. Rule pumps are tested to the highest standards to deliver the best performance at an economical price. Float switches are not required for these fully automatic pumps. Controlled via built in sensors, the pump will turn on every 2.5 minutes for about 1 second to sense for water. If water is present, the pump will sense