Double Ball Bearing start system set including : Clutch bell, special Hardened Pinion , choice of 14-15-16T ( one pinion per set) , Ball Bearings, start block and hardware are included in a set, and those are   a direct replacement for Millenium 2 / 3  and Dyna-X start system. Reduces movement of the Pinion during Extreme 3D, and protecting the pinion from been exposed to dust. Anodized in Clear.