About this item Made of quality steel, durable. Size: 5.51*1.89 inch(14*4.8 cm); Color: silver Easy to use, it is designed to measure the degree of wear of the chain specifically, It is convenient for you to determine whether you need to replace the chain. Measurement method: If the two ends of the chain checker cannot be put into the chain gap at the same time, that means the chain works normally. If it can be inserted in .75 size, that means the chain need be replaced soon. If it can be inserted in 1.0 size, that means the chain must be replaced immediately. Suitable for most road bike, mtb, mountain, bicycle chain, etc.