Ball Bearing Universal ball cap, (4th main) Uses a high quality sealed bearing to eliminate oil leaks, vibration and crankshaft fatigue. Can be installed without removing the transmission to machine the tail shaft!! Has new cast silicone bronze housing, no need for an exchange core. Ball on drive shaft tube has to be cut 3/8” and the sleeve that is supplied in this kit has to be machined to fit your tail shaft. Instructions included.