Details: The Topeak Modula Cage II Bottle Holder lets you secure both store bought plastic water bottles and reusable cycling bottles to your bike frame for easy access hydration. The adjustment system is smooth and intuitive. All you have to do is push the button on the bottom of the cage s base and slide the cage to the appropriate diameter width. The aluminum and engineering grade plastic construction means the Modula Cage II can stand up to the bumpiest bike trails and fastest road races without breaking or releasing its grip on your water bottle. The cage also has two rubber sections on the aluminum arm so your bike bottle won t rattle around. Bundle Includes: Topeak Modula Cage II Bike Bottle Holder (2-Pack)