Specifications: Head Size Fit: M for 54-57cm, L for 58-61cm, XL for 60-62cm. Material: PC Shell with EPS Inner Buffer and Polyester Strap. Technology: Integrated. Internal Size: 17x22cm. Outside Size: 34x22x19cm. Weight: M-350g, L-380g, XL-390g. Vents: 18. Certificate: CPSC 1203 and EN1078. Package Includes: 1 Mountain Bike Helmet, 1 User Manual, 1 Sun Visor, 2 Screws. This mountain bike helmet complies with U.S. CPSC and E.U. CE Safety Standards for Bicycle Helmets, offering versatility and protection for your adventures. The construction features a full coverage polycarbonate outer shell fused to an impact-absorbing EPS foam layer for durability without excess weight. The sleek design incorporates 18 wind tunnel vents and internal channeling for heat dissipation during long rides. It includes washable and removable padding and a large visor for sun protection. An adjustable rear dial system allows for a customized fit, with three sizes available to fit most youth, adults, men, and women.