Johnson F4B-19 flexible impeller pump 12/24v DC options 1/2 inch NPT(F) 0.6 bar 48 lpmJohnson F4B 19 flexible impeller pump 12 24v DC options 1 2 inch NPT(F) 0. 6 bar 48 lpm With their high level of flexibility, these pumps are ideally suited for use in boats as bilge and deck wash pumps, freshwater pumps, refueling pumps for oil and diesel These pumps may be combined with a vacuum switch for automatic operation. Heavy duty motor to provide long service life even under heavy use; motor has additionally a built in thermal overload for