Protect yourselfagainst expensive propeller theft. Machined from naval brass andhardened stainless steel, this lock features a free-spinning collarthat will turn if attacked by gripping tools, without loosening thelock. Replaces the original propeller nut and washer Mercruiser: Alpha I, Bravo I, TRS OMC: Cobra and Ding Cobra Outboards Mercury/Mariner: 70 hp and larger Johnson & Evinrude: 140 hp and larger