Designed to protect the oil pump and cam plate from debris off the chain-tensioners or other particles that may come loose in a Twin Cam engine. Great to put in when doing a cam bearing job. Keeps cam bearing rollers from dropping into the center section of your engine, which could ruin the oil pump and cam plate. Does not restrict oil flow - in testing the engine returned the same amount of oil back to the oil tank in an allotted amount of time; the screens de-aerate the oil more, which drops oil temperature 5-10°F. Easy-to-install and clean. Made in the USA. For use with OEM oil pumps only..