Description: High tensile steel. The internal thread has high precision, smooth rotation, and convenient maintenance. Specifically designed for e-bikes, the ratchet mechanism is strong and durable enough to withstand the enormous torque generated by the electric motor. Features: Smooth rotation and high quality. 7-speed with large climbing gear, 14-28 Teeth. Explore uses Shimano Freewheel. *Note: It is recommended to be replaced by professionals or under their guidance.