Jabsco-Rule 500 GPH Standard 12V Bilge PumpWith over 50 years of excellence Jabsco-Rule provides superb pumping performance. Helps keep your bilge clear of water. Going through rigorous engineering and testing bring flow efficiency in even the toughest conditions. Threaded Discharge - provides easy install and maintenance; Back Flow Prevention - reduces odor and helps keep bilge clean by reducing leftover water in the bilge; High Flow - provides better flow at consistent amperage through impeller optimization; Hidden Air Vents in the body - Helps with the check valve and preventing locking during plumbing installations; Built-in Thermal Cut-Off - bestows extra protection for the pump and vessel; Specifications: Flow Rate: 500 Gallons Per Hour (GPH); Voltage : 12 VDC; Fuze Size: 4 Amp; Amp Draw: 2.7; Height: 3-7/8"; Width: 2-7/8"; Port Type: 3/4" Hose Barb; Installation Information: Before installing or servicing the pump disconnect the power; Use stainless steel hose clamps to attach the discharge hose to the hose barb; Discharge houses for thru-hulls should be at least 8" above the water line; Check valves should not be used to prevent siphoning into the boat; A check valve should only be used to prevent the cycling of an automatic bilge pump from backflow of the discharge line ; Installation Instructions: Remove pump from the base by using the push tabs located on the side of the pump; After inserting the pump into the base push down until an audible sound is heard.; *Stainless Steel Flathead screws of an appropriate length is recommended to secure the pump but not penetrate the hull. Ensure water is unable to penetrate the screw holes.; Issues that can reduce the flow of a bilge pump: Length of discharge pipe; Number of bends; smoothness vs. roughness of pipe/fitting interior; Technical Datasheet