Canton - Accusump Check Valve 1/2” NPTCheck Valve ensures all the oil being discharged out of an Accusump goes to lubricate the engine bearings and is not fed back toward the pump. For use in systems where a remote oil filter or a cooler is used. Uses 1 2" N. P. T. female threads. Features: *Uses 1 2" NPT female threads *Made In USA *Canton Racing Products has been building oil pans and engine related products for racing and high performance applications since 1981