These Steel Super Locks with lash cap recess feature a 10? lock angle and 3/8" valve stem size. They are recommended for all race applications because Super Locks have a wider angle (10?) that better distributes the ever increasing valve spring loads over the retainer than typical 7? locks. Precision-machined out of super-tough, fatigue-resistant metal alloy, Super Locks fit any COMP Cams 10? retainer.