McGard Premium Propeller Lock Set For Bravo III/Blackhawk 1 14 Thread Size. 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. Features of McGard 74053 Premium Propeller Lock Set For Bravo III/Blackhawk 1 14 Thread Size Best protection available against costly propeller theft Offers 24 hour protection during use storage and transit Constructed of naval brass and hardened stainless steel for maximum security See long description for compatibility Thread Size: 1-14; Hex Size: 1-7/16; Overall Length: 1.025 Package Contents: McGard 74053 Premium Propeller Lock Set For Bravo III/Blackhawk 1 14 Thread Size McGard 74053: Premium Propeller Lock Set For Bravo III/Blackhawk 1 14 Thread Size