Vittoria Air-Liner Protect Tubeless Insert – XC Trail 29 x 2.1-2.4″. Air-Liner Protect Tubeless tire inserts provide enhanced tire protection from the most extreme impacts shielding your wheels from the unforgiving elements of the trail. Constructed from a durable polymer foam ensuring long-lasting product life allowing riders to confidently tackle the most demanding trails and terrains. The design provides a robust barrier between the rim and the tire offering unprecedented protection against punctures sidewall slashes and pinch flats.