Features:Made of full CNC precision machining aluminum alloy, anti-slip, light weight and durable.Easy to install and remove, convenient for you to use.With this seat post tube adapter, you can change the bicycle seat tube to the size you want.Suitable for MTB bike, mountain bike, road bike, etc.Please check the outer diameter of your bicycle seat tube. Measure the inner diameter of the old clamp. Or measure the outside diameter of the seat tube. Then make the right choice.Specification:Condition: 100% Brand NewMaterial: Aluminum AlloyColor: blackOptions: 27.2mm to 28.6mm, 27.2mm to 30mm, 27.2mm to 30.4mm, 27.2mm to 30.8mm, 27.2mm to 31.6mm, 27.2mm to 33.9mmSizeLengthWeight27.2mm to 28.6mm60mm/2.36inch13g27.2mm to 30mm60mm/2.36inch22g27.2mm to 30.4mm60mm/2.36inch29g27.2mm to 30.8mm60mm/2.36inch25g27.2mm to 31.6mm60mm/2.36inch37g27.2mm to 33.9mm60mm/2.36inch54gPackage list:1 * Bike Seatpost Tube Adapter.