Full carbon material: Made of solid carbon, lightweight and portable, wear-resistant, no rust, no corrosion. Features a fine frosted pattern, beautiful and elegant. [Reverse Offset]: Unlike straight tubes, 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, enhancing leg range of motion and helping achieve the optimal riding position. Provides a freer, more stable, and comfortable riding experience. [Adjustable]: Offers optional seatpost length for improved riding height and angle. Adjustable head allows for easy installation. Front and rear screws enable flexible saddle angle adjustment. Clear scale markings allow precise seat tube length adjustment. [Size and Style]: 31.6mm diameter, 400mm length. Compatible with mountain bikes, road bikes, folding bikes, and BMX bikes, offering good versatility. How to choose a size: Check for size markings on the existing seatpost and match accordingly. If no marking is present, measure the seatpost diameter and select the same size. Alternatively, measure the inner diameter of the frame tube and choose the appropriate size. Dimensions: 3 x 3 x 32 cm Material: Carbon fiber Color: Black Package Contents: 1 x Seat tube (31.6-400mm) Note: The package includes only the items listed above. Other products are not included. Note: Lighting reflections and display differences may cause slight color variations between the image and the actual item. Measurement error allowance: +/- 1-3 cm.