【Maximum Load and Stability]】- Sturdy aluminum alloy construction supports cargos up to 9 kg (20 lbs). 【Adjustable】- Adjustable to fit to different bikes, retracted for easy storage. 【Easy Installation】- Easy to install with included rubber pad and L-wrench. 【Versatile & Convenient】- Carry your cargo with ease and efficiency, ideal for panniers, backpacks, baskets, etc. < h2>Product Description This support bracket is made cast aluminum alloy under pressure / extruded and durable. This material is generally used for bike frames and components, so it's as tough as your bike. The high quality material and the manufacturing process reinforce it for extra strength. Note: As different seatpost bikes don't have the same size and installation angle, please use the pads when you install it. And please install tightly without any play, then load your package. Due to cargo loading, put it in a position different from the scaffolding, which leads to stress points. Due to the different pressure,