Bicycle Chain Quick Release Links: Smooth edge will not damage the bicycle chain, easy to use without tool, suitable for 6/7/8/9/10 bicycle chains. ToolBicycle Chain Wear Indicator: Allows you to quickly assess the wear and stretch of the chains, help you decide whether to change a new one or not. Pl Bicycle Chain Link Pliers: Quickly remove the connecting links, advanced tool for opening and closing, chain link remover and connector. Spl Bicycle Chain Splitter Breaker Tool: Very smart, easy to break, easy to re-chain, unique groove on the top allows you to see how far you have ejected the peg and remove the cut chain with the peg. ToolPremium Bicycle Chain Tool: Made of K5 steel + carbon steel High quality carbon + manganese steel,Sometimes the metal may oxidize.