Allen hex key that fits over grease zerk. For use with QA1 ball joints. QA1's patented Ultimate Ball Joints are 100% owner rebuildable. Our spanner socket fits a 1'' socket or wrench for easily adjusting QA1 ball joints. To set ball joint pre-load, use the Allen hex key that fits over the grease zerk on all QA1 ball joints. Order the parts individually or together in the ball joint tool kit.