Material: Aluminum Alloy Size: Rack platform: 35.5cm x 14.5cm(20″ x 5.7″); Main Post: 54cm (21.3″) Quick release mount is suitable for seatpost diameter under 33mm only. If your bike’s seat post diameter is larger than 33mm, this rack cannot fit your bike. thanks for understanding. Quick release mount install at seatpost, easy to adjust. You can adjust the rack via the screws under the rack With side frame, protect your luggage not rubbed by wheel. With rear reflector.Quick release mount at seat post. Suitable for seatpost diameter under 33mm only. Fits V-brake and Disc brake bike. It is adjustable for many kinds of bike, 26″ 700C fits well.