Size(31.8mm) - The seatpost clamp has an inner diameter of about 31.8mm and will suitable for seat tube diameter 27.2MM, 28.6MM size. Size(34.9mm) - The seatpost clamp has an inner diameter of about 34.9mm and will suitable for large bore seat tube. Material - This bicycle seat tube clamp is made of high-quality aluminum alloy with anodized surface, which is light weight, high hardness, anti-corrosion, anti-rust, sturdy and durable. Easy to install - The bicycle seatpost clamp has a quick release and fixing non-slip nut, very easy to install and use, no complicated steps or procedures, it is very convenient. Easy height adjustment - Quickly release the clamp, which makes it easy to adjust the seatpost height, and makes the seat height adapt to your height, which is very practical, safe and stable. Wide application - The seat post saddle clamp is suitable for all kinds of bicycles, such as road bikes, mountain bikes, children's scooters with lift bars, folding bikes, crawler vehicles, etc. Weight: 72g (31.8MM)/80g(34.9MM) Quantity: Two pieces Color: Available in black/red/blue/gold/titanium Size: Available in 31.8mm/34.9mm