Features: The bicycles chain square ruler is mainly made of stainless steel, which can be used for long-time and rustproof. The-surface is smooth and free of burrs. It can quickly detect chain wear and can be used on almost any bicycles, such as city bikes, mountain bikes, road bikes, etc. The circulating chain inspector is a good tool for checking the degree of chain wear. Therefore, you can decide whether to replace the chain. The chain inspector is portable, easy to store, and does not take up too-much space. Easy to operate with one hand. The chain hook design allows you to easily handle chain maintenance. With measurement number, you can quickly measure the length of screws. Specifications: Material: Steel Color: Black/Silver Length: Approx. 12.5cm/4.92inch Note: Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1x Bike Chain Checker