Self-priming: chucks into a standard 1/4" or 3/8" drill motor and pumps up to 3-1/2 GPM. Marine-empty water tanks, bait wells, fish wells, remove heated oil from engine, bail water from small boats at dockside.*1/4" (6.5mm) diameter shaft. *Self-priming to 3ft (1m). *Pumps up to 3.4 gpm (13 lpm). Included w/pump: two 3/4" garden hose thread port adapters.