Description The rack is 55cm long and 14.5cm wide, and seat post is 35cm long and 14.5cm wide. This carrier rack is made of durable aluminum. This material is usually used for the frames and components, so you can safely mount it on your back since it is as strong as your bicycle. Features - Color: Shown in the pictures. - Material: Aluminum. - Size: Approx. 52 * 16 * 6cm/ 20.5 * 6.3 * 2.4 inch (L*W*H). - Fit for rod within 33mm. - Highly strong aluminum alloy with imppecable craftsmanship. - Sturdy structure with heavy duty capacity which can bear 50kg weight. - Retractable, fit for most of bike. Easy to install. Packing list: 1 * Universal Seatpost Rack Bike Carrier Rack Rear Frame-Mounted Heavy Duty Cycle Accessory