This is Cush Core's XC Tire Insert set with tubeless valves. Features: A smaller, lighter version to fit XC tire sizes and riding style An engineered foam insert that mounts inside a mountain bike 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 mountain bike 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