1. This bicycle rack is made of a sturdy aluminum alloy structure and can withstand a load of up to 10 kilograms (20 pounds). Depending on the thickness of the rider's seat tube, it can be slightly increased to 22 pounds. 2. [Adjustable]: The length of the rack can be adjusted between 32 cm and 50 cm. It is suitable for seat tubes with a diameter of 22 - 35 mm. 3. [Easy to install]: It comes with 4 screws and can be easily fixed on the seat post. It can be firmly and easily attached to the bicycle seat post. The height is appropriate, so items will not scratch the wheels and affect the ride. 4. [Large capacity]: The rear bicycle rack is very suitable for both long - distance and short - distance trips and can accommodate a large number of daily necessities. It is suitable for bicycles of various sizes. 5. [Usage]: It is an ideal choice for travel and can help you carry enough daily supplies. It is very suitable for hanging baskets, backpacks, bags, etc.!