- Design: The bike crank arm bolt features a hollow integrated chainring screw design, used for securing the crank and chainring's arm. It is an essential component of your bike's performance - Quality material: This m15 bicycle crankset bolt is made from quality aluminum alloy, ensuring durability and resistance to wear and tear. Its sturdy construction prevents deformation, allowing for long term use - Easy installation: This bike crankset screw is easy to install, making it a great replacement for damaged or old parts on your bicycle - Appropriate size: With an inner diameter of 15 mm, a length of 2.5 cm, and a width of 2.1 cm, this cycling accessory is compact in structure and lightweight in design, nice for portability - Wide application: This bikes hollow fixing is ideal for various types of bikes such as mountain bikes and road bikes among others; it also makes a practical accessory tool gift for cycling enthusiasts Specification: - Material: Aluminum Alloy Size Chart: Total Size: 2.1 cmx2.1 cmx2.5 cm/0.83 inchx0.83 inchx0.98 inch Inner Diameter: 1.5 cm/0.59 inch Package Includes: 1 Bike Crank Arm Bolt Note: Please allow slightly errors 1-2cm differences due to manual measurement.