Best Of Source Aluminium Alloy Bike Water Bottle Holder Cage Rack Mount - Black Made of high quality 7075 aluminum with anodised surface Simple and practical design Sturdy structure, prevent deformation damage Lightweight and portable with just 42 gram Suitable for varied types of bikes, including mountain bike, road bike and folding bike; Compatible with 30.9 mm - 31.8 mm diameter handlebar or seatpost