Aluminum alloy seatpost clamp is a quick release style clamp, it is convenient and useful. And it can be adjusted on the way even without any other tools. High hardness and lightweight design make it more attractive to people. The beautiful color and delicate workmanship make it a good gift for people who like cycling. It is constructed of aluminum alloy material. There are two specifications for you to choose from: 40mm, 41mm. It is suitable for mountain bike and road bike. Item Name: Bicycle Seat Clamp Material: Aluminum Alloy Features: Sturdy, Quick Release, High Strength Size Details: 40mm: Caliber: 4cm/1.57" (Approx.) 41: Caliber: 4.1cm/1.61" (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 Bicycle Seat Clamp