O-ring design retains the tool in wrench or socket while flange design allows downward force to be applied to tool. Designed for use with 7/16" combination wrench to allow for maximum rotation without touching engine cases. For use on big twin (excluding twin cam) with slotted screw tappet oil filter screen cover. Can be used without removing exhaust pipes on most bikes. Tappets should be serviced every oil change.
