Sierra 18-9839 Bearing Cup Driver Sierra bearing cup driver installs bearing cup in top cover of drive shaft of MC-I, R-MR, Alpha One drive units and outboards. Interchangeable with Mercury Marine 91-38918T California Residents WARNING Cancer and Reproductive Harm - P65Warnings.ca.gov Other Details Google Product Type Special Tools Wiser Yes Product MPN 18-9839 Product UPC 808282109479