McGard Locks are fully machines from high quality stainless steel and are through-hardened. This proven design features a free spinning collar that turns it attacked by gripping tools without loosening the lock. Best protection available against expensive stern drive theft. Twin Drives sets include 2 locks and 1 key MerCruiser Alpha ; Bravo I-III (Incl. X & XR); Blackhawk; OMC Cobra ; King Cobra ; Volvo SX ; DP-S ;