Cush Core Gravel/CX Tire Insert Set. Features: Sizes for Gravel and CX tires, allowing lower tire pressures, more comfort, and better grip An engineered foam insert that mounts inside the tire. It divides the inner volume of the tire in half, with air underneath the tread and the CushCore insert next to the rim Absorbs impacts, reduces vibration and adds lateral stability to the tire This system is designed to be used with tubeless ready or tubeless converted rims and tires, as well as standard tubeless sealant Doesn't absorb sealant like other tire inserts on the market Includes special tubeless air valves that allows air to move through the valve without becoming obstructed by the insert *Tubeless valve not included with single packs Amazon.com sales are strictly prohibited by the Manufacturer Specs: Package:single with valve Wheel Size:700c Width Rim:tire 33-46c/rim 17-21mm Weight:110g