1、Made of stainless steel,cover is polished, it has high slip resistance, high hardness, wear resistance, durability, high precise, accurately display. 2、Portable, compact and durable bicycle chain indicator, compatible with all chains, you can take it with you easily. 3、After riding for a long time, the chain will wear out more quickly, it can quickly measuring the degree of chainwear and convenient for replace. 4、If the two ends of the chain checker cannot be inserted into the chain seam with the size of 0.75% and 1%, the chain elongation is within the normal range, otherwise, the chain needs to be replaced. 5、It can be used not only as a bicycle chain wear indicator, but also as a chain hook and bolts measuring tool, for disassembly and assembly of nuts, valve cores and extension rods.