Protect yourself against expensive propeller theft with a McGard boat propeller anti-theft lock, featuring the same patented design as our stern drive and outboard motor locks. A free-spinning collar will turn if attacked by gripping tools without loosening the lock. Constructed of naval brass and hardened stainless steel replaces your prop nut. Once installed our boat lock system offers maximum security for 24-hour protection. You don't have to remove the lock to use your boat!
Thread size - 1-14. Fits the propellers on the following MerCruiser stern drives: