Specifications: Made of aluminum alloy material, it has high hardness and strong wear resistance. It has anode surface treatment process and equipped with quick release lock design. The hollow design make it lightweight and easy to carry. There are three specifications for you to choose from, the 28.6mm seat tube clamp is suitable for 25.4mm seat tube, most of which are used for road bike or fixed gear bike, while the 31.8mm seatpost clamp is suitable for 27.2mm, 28.6mm seat tube, and the 34.9mm seat tube clamp is suitable for seat tubes such as 30.4/30.8/30.9/31.6mm. This quick-release locking seatpost clamp is a durable and lightweight tool, adding some beautiful colors to your riding and making it easy to adjust the height of the seat post. Item Name: Seatpost Clamp Material: Aluminum Alloy Features: High Hardness, Wear-Resistant, Hollow Design, Lightweight, Easy to Carry Inner diameter: 28.6mm/1.13", 31.8mm/1.25", 34.9mm/1.37" (Approx.) Package Includes: 1 x Seatpost Clamp