This 120 rear Sprocket has 9 mounting holes evenly spaced for 520 chain and fits hubs that are 7 1/2 inch diameter. This Sprocket will fit 1974 and newer Pursangs except 1976-77 125 and 200 Pursangs. Fits all Fronteras. Fits 1975 and newer Alpinas. Fits Sherpa T models 124,125,150 and 151.