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: Mercruiser Bravo III (up to 2003), Blackhawk This product may contain globally sourced materialscomponents