This Steel Super Lock Featuring A Lash Cap Recess, 10 Degree Lock Angle And 5/16" Valve Stem Size Is Recommended For All Race Applications. Super Locks Have A Wider Angle (10 Degree) That Better Distributes The Ever Increasing Valve Spring Loads Over The Retainer Than Typical 7 Degree Locks. Precision-Machined Out Of Super-Tough, Fatigue-Resistant Metal Alloy, Super Locks Fit Any Comp Cams 10 Degree Retainer.