comingfit 310lbs Capacity Adjustable Bike Luggage Cargo Rack-Super Strong Upgrade Bike Luggage Carrier 6-Strong-Legs Bicycle Luggage Carrier Design with high quality aluminum alloy and quick release. Fits V-brake and Disc brake bike; For fat bike, road bike, mountain bike,etc. (Kids' bike and Trek Verve can not be used) ; THE INSTALLATION INSTRUCTION LINKhttp://www.mediafire.com/file/5dc32y7pc5rvn0i/Installation+Instruction+of+140kg+310lbs+Rack.pdf Seat Post' diameter should be 0.85-1.3" and donot have shock absorber; Shelf Length 22", Width 5.7"; Panel Length 14"; Width 6" ; Weight limit: 330lbs Includes Red Rear Reflector Lamp and Elastic Cords, which can make you safer to riding at night and keep your luggage secure.