Specifications: It is made of premium quality aluminum alloy material and stainless steel material for the gasket so it is very safe and durable for you to use. Furthermore, due to its high quality material and fine workmanship, it comes with solid construction so it would be very secure and stable for you to use. What's more, it is very easy to use so it would be very convenient for you. In addition, it comes with stainless steel gasket and it has special hard anodized design for the hub so it is very wear-resistant. Therefore, it would be your best choice for bike supply accessory. Item Name: Center Lock Adapter Material: Aluminum Alloy, Stainless Steel Features: Durable, Lightweight, Easy to Install Size Details: Maximum Outer Diameter: 5.4cm/2.13" (Approx.) Center Diameter: 4.4cm/1.73" (Approx.) Notes: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes: 1 x Center Lock Adapter 1 x Center Lock Cover