Supertech 6mm Single Valve Lock Conversion Keeper Set of 32Supertech performance valves feature a radial style single groove on the valve stem and require matching single groove valve keepers to match. Single groove valves are preferred for performance orientated and race engines as the top part of the groove provides a cushion for the lock and aids in valve stem protection against uncontrolled and excessive valve movement. In addition, the single groove design greatly extends valve stem life by restricting