The best protection available against costly propeller theft. Once installed the McGard propeller lock offers 24 hour protection during use, storage and transit. A free-spinning collar will turn if attacked by gripping tools without loosening the lock. Constructed of naval brass and hardened stainless steel for maximum security. Fits the following stern drives and outboard motors: MerCruiser Alpha I, Bravo I (incl. X and XR), TRS, Vazer, OMC Cobra and King Cobra, Mercury/Mariner 70 hp and larger (2 stroke), Mercury 40 hp and larger (4 stroke) (ex. 225 hp 4 stroke before 2005), Optimax 75 hp and larger, Verado 135 hp and larger, Johnson/Evinrude 150 hp and larger (2 stroke). This product may contain globally sourced materials/components.