Sierra brand gear lubricants are specifically formulated to perform in the marine environment and no matter what you own chances are Sierra has a gear lubricant for you. Sierra Premium, Hi-Performance Synthetic Blend, and Full Synthetic Lube are all GL-5 rated to provide maximum protection under extreme pressure and meet or exceed the requirements of all major OEM engine manufacturers. Sierra Type C gear lubricant is only for use in older OMC outboard and sterndrive engine applications that are equipped with electric shift. All Sierra gear lubricants contain additives specifically manufactured for the marine environment. Sierra gear lubricants will keep water suspended longer than the leading OEM supplier. With our full range of gear lubes, no matter what type of engine package you own Sierra has the lube for you!