Full carbon material, : Made of solid carbon, light and portable, wear-resistant and , no rust, no corrosion. Fine frosted pattern on the , beautiful and generous. [Reverse Offset]: Unlike the straight tube, the front end of this seatpost is offset by 20 to 25 mm. This design increases the distance between the saddle and the seat tube, allowing the saddle to move further back, increasing the range of motion of the legs and finding the best riding position , allowing you to feel more free while riding , more comfortable. Stable and more comfortable. [Adjustable]: With this optional seatpost length, you can get a better riding height and a better riding angle. Adjustable head for easy installation. Adjust the front and rear two screws, the saddle can change the angle flexibly. The scale is clear and the length of the seat tube is adjusted accurately. [Size and Style]: 31.6mm, Length: 400mm. It is suitable for bicycles such as mountain bikes, road bikes, folding bikes, and BMX bikes, and has good versatility. You can choose the matching sea mail according to your wishes How to choose a size: There is usually a size mark on the seatpost, and you can buy it according to the size mark. If not, measure the diameter of the seatpost and choose the same size as the seatpost. Or measure the inside diameter of the frame tube and choose the proper size. size: 3 x 3 x 32 cm Material: carbon fiber colour: black Package Contents: 1 x Seat tube(31.6-400mm) Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.