Seatpost conversion set is easy to install and remove, no other tools are needed, just a few seconds to install, convenient for your use. Not easy to rust, not easy to paint off; CNC cutting, neat cutting, smooth lines. Various size conversions can solve the problem of unsuitable frame and seat tube sizes, and you can change the size of the bike seat tube as needed. It is constructed of aluminium alloy material. The bike seatpost shim is available in many styles for you to choose from. It is suitable for bicycle, mountain bike, city bike, road bike. Item Name: Bike Seatpost Shim Material: Aluminium Alloy Features: Easy to Install, Durable, High Hardness Style: Style A: 22.2mm to 25.4mm Style B: 25.4mm to 27.2mm Style C: 25.4mm to 28.6mm Style D: 27.2mm to 28.6mm Style E: 27.2mm to 30.4mm Style F: 27.2mm to 30.8mm Style G: 27.2mm to 31.6mm Style H: 27.2mm to 33.9mm Style I: 31.6mm to 33.9mm Style J: 33.9mm to 34.9mm Size Details: Style A/C/D/E/F/G/H/I, Height: 5.9cm/2.32"(Approx.) B, Height: 5.8cm/2.28"(Approx.) J, Height: 4cm/1.57"(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 Bike Seatpost Shim