It can be used on all 139QMB 4 stroke 50cc/60cc/80cc scooters, and DIO 50 ZX50 2 stroke scooters as well.
This performance torque driver features 6-groove design ( (3 curve grooves and 3 straight grooves), which will protect your drive belt from slipping,also lowering driving temperature, and making full use of the power of engine.