The bicycle water bottle Holder Adapter is made of Aluminum alloy safe and environmentally friendly, no peculiar smell. Easy to install, stable and heavy duty. Suitable for mountain bikes, road bikes, folding bikes, etc. keeps your bike drink holder in place so you can ride harder and longer. Not afraid of severe cold and heat. It has strong toughness and is not prone to fracture and damage under low / high temperature conditions. Specification: Material:Aluminum alloy Size Chart: Size: 78×34mm/3.07×1.34inch Package Includes: 1 Piece Bicycle Water Bottle Holder Adapter 1 Piece Thick Washer 1 Piece Thin Washer 1 Piece Gasket 1 Piece 3.0mm Hexagon Socket(5 Pack) Note: 1. Please allow slightly error due to manual measurement. 2. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! 3. Wish you a wonderful on-line shopping!