The Vittoria Air-Liner Light XC Trail is an insert for your MTB tire that helps it perform at a higher level and become more reliable. At just 55 grams, it will go virtually unnoticed as you ride. The liner improves grip at lower pressure, adds to overall stability and prevents tire burping. The liner comes with a 40mm tubeless valve to help with easy installation. The Vittoria Air-Liner Light XC Trail insert is a great way to bump up the performance of your favorite trail bike.