CushCore Pro Set - Includes (1) Tire Insert, (1) Presta Valve & (1)  Easy At-Home Installation, Bicycle Tire Inserts, Helps Improve Ride Quality, Fits a 2.1"-2.6" Tire (Single, 29”) As a company, CushCore is based on a new concept of tire suspension. Suspension systems work by utilizing a spring and a damper to diminish the effect of bumps and dips on the overall quality of your ride. Now, with CushCore, the pressurized air in your tire acts as the spring and the CushCore tire inserts act as the damper. Go bigger, corner harder, & ride faster with CushCore!