Feature●Fits all mercruiser Alpha one, Pre Alpha, Generation 2, Bravo One; Trs outdrives will also fit Mercury / Mariner outboards 150HP an.●Fits the 4 3/8" retainer nut, not fits Bravo 2, 3, XR, or TR.●The tool set are used to remove and install driveshaft housing (upper) bearing retainer nut (By U joint shaft) on #1 (1982 and earlier), R, MR, Alpha Gen 1 (1983 -1990), Alpha Generation ll (all ), MC1, and all Bravo and Blackhawk units.●Package Contents: 1xDrive Bearing Retainer Spanner WrenchDescription Fits all mercruiser Alpha one, Pre Alpha, Generation 2, Bravo One; Trs outdrives will also fit Mercury / Mariner outboards 150HP an.