Vittoria Air-Liner Light Tubeless Insert - Gravel, 700 x 37-40The Air Liner Light is an ultra fast and light weight tire insert intended for the performance rider or anyone looking to improve the reliability and performance attributes of their ride. Designed specifically for gravel tubeless tires, with tire widths ranging from 37 40mm, this innovative insert revolutionizes the wheel tire system for gravel applications Improved grip at lower pressure with greater tire stability Lowered risk of tire burping and