Constructed from lightweight spring aluminum alloy, perfect for those who want a stylish cage to lighten their load as they ride. Oval and ergonomic design helps to strengthen its hold, keeping bottles securely in place while providing easy access for riders. Great for rides around town or for touring. 40 Gram, Lightweight Aluminum Cage With Thermo Plastic Base Holder Installation method: 1. Remove existing screws in frame mounting holes. 2. Insert screws through the holes in the cage and thread into frame holes.Be careful not to over-tighten the screws. 3. Periodically check to make sure that the screws remain tight. This bottle cage will mount to the existing water bottle mounting holes on your bike's frame. Note: An additional bracket may be needed if your bicycle does not have factory water bottle mounting holes. Tips：Suggested metal kettle wrapped with cloth cover, Avoid scratches.