Description: Quality Material: The Bike Seat Post Shim Tube is made from quality aluminum alloy, ensuring durability and long term use. It is sturdy and wear resistant, great for regular cyclists.Easy to Use: This Bicycle Seatpost Converter is simple to install and can help you adjust the size of your bike seat post without the need for additional tools or seat post replacement. It is user friendly and easy to use.Bicycle Seat Post Conversion: The Bicycle Reducing Sleeve features a compact design and lightweight construction, making it easy to carry around. It helps solve the problem of mismatched sizes between your bike frame and seat.Wide Application: This Bike Seat Tube Adapter is ideal for various types of bikes including mountain bikes, road bikes, adult bicycles, etc., making it a versatile addition to your cycling gear.Practical Accessory: The Bicycle Seattube Shim Sleeve makes a practical gift for family members or friends who enjoy cycling or biking sports. Specification: Material:Aluminum Alloy Size Chart: 28.6mm to 27.2mm:2.86cmx2.86cmx5.9cm/1.13inchx1.13inchx2.32inch30.4mm to 27.2mm:3.04cmx3.04cmx5.9cm/1.20inchx1.20inchx2.32inch30.8mm to 27.2mm:3.08cmx3.08cmx5.9cm/1.21inchx1.21inchx2.32inch31.6mm to 27.2mm:3.16cmx3.16cmx5.9cm/1.24inchx1.24inchx2.32inch Package Includes: 1Bike Seat Post Shim Tube Note: Please allow slightly errors 1-2cm differences due to manual measurement.