ITEM NAME:3x Bicycle Bike Seat Post Shim Tube Sleeve Size Reducer Seatpost Convert Adapter Description: Premium high quality aluminium alloy material,high strength, lightweight and solid enough To change your seat post size easily with this bushing without changing seatpost Full CNC precision machining with smooth edges which won't hurt your finger Suitable for MTB bike, mountain bike, road bike etc. Please check your bike frame seat tube outside diameter. Measure the inside diameter of your old clamp. Or measure the outside diameter of your seat tube (on your bike frame) Specification: Material: Aluminium Alloy Color: Black Size Chart: Length: 60mm/2.36 inch Size: 25.4 to 27.2 mm 27.2 to 31.6mm 28.6 to 31.8mm Package Includes: 1 Piece Bike Seatpost Shim Adapter (25.4 to 27.2 mm) 1 Piece Bike Seatpost Shim Adapter (27.2 to 31.6mm) 1 Piece Bike Seatpost Shim Adapter (28.6 to 31.8mm) Note: Please allow slightly difference due to manua l measurement. Color may be slightly different since different monitor. Thanks! DMO0009080519522369.Premium high quality aluminium alloy material,high strength, lightweight and solid enough. Color: Black. Full CNC precision machining with smooth edges which won't hurt your finger. Size Chart Color may be slightly different since different monitor.