Lixada Bicycle Bottle Cage Adapter Mount Adjustable MTB Road Bike Handlebar Water Bottle Holder Seat Post Mount Fits for: Seat post :30.9mm-31.6mm, Handlebars: 31.8mm Solid and durable Aluminum Alloy 7075 CNC finish, lightweight. Can be 360 degrees rotation, easy to install and remove. Includes hex screws for attaching a water bottle cage. Great kit for bike doesn't come with bottle cage mounting holes.