Worn or scored thrust washers and prop nuts can cause damage to your prop shaft and propeller face. Protect your drive system by changing your thrust washer and prop nut when replacing or inspecting your propeller. Fits Mercury/Mariner: 40-60 hp BigFoot 4-Stroke; 75-125 hp 2-cycle & 4-Stroke; 135-275 hp 2-cycle. Fits Force: 75 hp ('99); 90-150 hp ('95 and newer)Fits MerCruiser Alpha and Bravo I sterndrivesReplacesGLM 21300Mercruiser 77987A1, 13171, 12-835467, 12-8354671, 12-835467Q01Mercury 77987, 12-8354671, 12-835467, 13171, 77987A1Sierra Part No. 18-4220 For use with Force 90-150 hp ('95 up) Sierra Part No. 18-4220 | Thrust Washer for Mercury/Mariner, #18-4220