*Stock Is Limited!* New Triumph & BSA Mainshaft Gearbox Bearing. This is an Excellent quality bearing that is ready to be installed! Bearing installs on the inner gearbox cover on both Unit & Pre-Unit Twins. Fits Triumph T100 models from 1939-1959. Fits all Triumph Unit 650 & 750 models (Bonneville, T120, TR6, Thunderbird, 6T, Tiger, TR6C, Trophy, T120RV, TR6CV, T140, Etc) from 1963-1982. Fits all BSA 500 & 650 Unit Twins from 1962-1972. Also fits various Triumph Trident models and Triumph Pre-Unit 650 Gearboxes. Please refer to your parts catalog for proper fitment.*****Please check your parts book to ensure the best fitment!*****Made in the JapanO.E.M Part number is 60-3552, 21-0357, 24-4217, 57-3621 or S35-7