Propeller lock fits the following models: Stern Drive: MerCruiser: Alpha I, Bravo I (incl. X & XR), TRS, Vazer, OMC Cobra and King Cobra and for Outboard: Mercury / Mariner 70 HP and larger (ex 225 HK 4 beats before 2005) Mercury Bigfoot 40, 50, 60 HK (4-stroke). Optimax 75 HP and larger Verado 135 HP and larger. Johnson / Envirude 150 HP and larger (2-stroke)