Top quality U.K. made crankshaft alternator stud as fitted to most unit construction 650 and 750 Twins including T120, 120R, T120C, T120TT, Tiger, Trophy and Bonneville, T140, TR7, Bonneville and Tiger, etc. Measurements are 7/16″ x 1 3/8″ 26 T.P.I. this item was up until 1973 750 Twins and changed to 21-2183 (different threads) from 1974 onwards.