Description: 【Material】: This Bike Seat Post Clamp is made of steel, ensuring a secure and sturdy connection between your seat post and saddle rails. The angle of the clamp is adjustable for optimal positioning. 【Secure Fastening】: The Bicycle Seatpost Clamp features an M8 bolt thread with external hexagonal nut for tight and secure fastening. It's designed to be used with metal materials such as steel or aluminum. 【Compatibility】: This Bicycle Seat Post Clamp fits shrink head seat posts with an outer diameter of 22mm, and saddle rail heights of 6-7mm. An M13 wrench is included for easy installation. 【Note】: Please note that this product cannot be used with carbon fiber material seat posts or saddle rails. Only the bike seatpost clamp, not includes the seat post or saddle. 【Product Dimensions & Package Contents】: The Bike Seat Tube Clip measures 7.2cm/2.83inch in width with clamp pipe diameter 2.3cm/0.91inch. The package includes 1 Bicycle Saddle Clamp and 1 M13 wrench. Specification: Material: Steel Size Chart: Width 7.2cm/2.83inch; Clamp Pipe Diameter 2.3cm/0.91inch Package Includes: 1 Bike Seat Post Clamp 1 M13 Wrench(5 Pack) Note: Please allow slightly errors 1-2cm differences due to manual measurement.