Features: Make from high strength aluminum alloys, ensures its durability and resiliences against wear and tear. Features a hollowed out design that significantly reduces its weight. Enjoy a lighter bike without compromising on strength. The bicycles seatpost clamp utilizes a screw and nut locking system, which automatically adjusts angles and prevents deformation caused by concentrated stress when tightened. With its simple design, this bicycles seat tube clamp can easily installed without any hassle. Whether you have a mountain bike, or road bike, or hybrids bike, this clamp will provide a secure and adjustable fit. Specifications: Component: Aluminum alloys Color: Black/Blue/Red/Golden/Slivery Type: 31.8/34.9/28.6 31.8 Size: about 4.55x1.4cm/1.79x0.55inch, Inner Diameter: 3.180cm/1.25inch 34.9 Size: about 4.92x1.4cm/1.94x0.55inch, Inner Diameter: 3.49cm/1.37inch 28.6 Size: about 3x1.1cm/1.18x0.43inch, Inner Diameter: 11.26inch Package Includes: 1Pc Bicycles Seat Tube Clamp note: Please allow 1-2cm errors due to manual measurement, make surely that you not mind before order. Due to difference between different monitors, the picture may not reflect the actual color.