Bicycle Chain Cutter: Comes with a chain hook to secure the chain when replacing the chain, making it easy to grip and easy to cut the chain.The ejector pins are removable and replaceable, and the material is made of high hardness alloy CR-V, which is strong and durable. This item can measure chain extension by 0.75 and 1.0. If the tip of the chain is unnecessary, it is time to replace.