Features: Made of high quality plastic material, durable and practical. It can replace the old bearings when the old dust cover was damaged. No need to use tools, manually press in and install it, it is very convenient, after the crank is locked, there will be no looseness. One bike needs two. Specifications: Item type: Medium shaft bearing protection cover Inner diameter: 24MM Suitable for crankshaft diameter 24MM. Size:36.8*25mm Material: engineering plastic Color:Black Function: waterproof and dustproof Package includes: 2* bearing protection covers Notes: 1.Due to the difference between different monitors, the picture may not reflect the actual color of the item. We guarantee the style is the same as shown in the pictures. 2.Due to the manual measurement and different measurement methods, please allow 1-3cm deviation. Thanks!