Brand new, genuine Mercury Marine/Mercruiser Cylinder Nut. This is a factory original equipment part, not aftermarket. Fits: 35 HP - 35 35 HP - 35 (2 CYL.) 40 HP30 JET - 30 JET 40 HP30 JET - 40 (4 CYL.) 40 HP30 JET - 40 (4 CYL.) 45 HP - 45 (4 CYL.) 45/50 HP - 45 (4 CYL.) 45/50 HP - 50 (4 CYL.) 50/60 HP (3 CYLINDER) - 60 (3 CYL.) MARINER 70 - 70 MERC 40 - 402, 40 (2 CYL.) MERCURY 70 - 70 (3 CYL.) .