Triple 8 Gotham MIPS Helmet for Biking, Skating, Rollerblading, and Roller Derby, Blue Matte, S/M Urban-style helmet with Multi-directional Impact Protection System (MIPS) technology that reduces rotational forces during impact Vented ABS shell with subtle brim, and lightweight Conehead EPS liner offers excellent airflow and maximum protection Complies with U.S. CPSC Bike and ASTM F-1492 Skate safety standards; ideal for biking, skateboarding, rollerblading, BMX, derby, and commuting Includes two sets of removable, washable, terrycloth Sweatsaver liners, adjustable dial system, and chin strap with side release buckle for custom fit Size XS/S fits 19.7  21.5 in (50  55 cm), S/M fits 21.5  22.75 in (55  58 cm), L/XL 22.75  24 in (58  61 cm); manufacturers 180-day warranty