Specifications: Head Size Fit: M for 54-57cm (21.25-22.44in), L for 58-61cm (22.83-24.0in), XL for 60-62cm (23.62-24.4in) Material: PC Shell + EPS Inner Buffer + Polyester Strap Technology: Integrated Internal Size: 17*22cm (6.7*8.67in) Outside Size: 34*22*19cm (13.38*8.67*7.48in) Weight: M - 350g (0.77lb), L - 380g (0.84lb), XL - 390g (0.86lb) Vents: 18 Certificate: CPSC 1203 + EN1078 Package: 1 x Mountain Bike Helmet, 1 x User Manual, 1 x Sun Visor, 2 x Screws SAFETY FIRST: This high-performance mountain bike helmet meets U.S. CPSC and E.U. EN1078 safety standards for bicycle helmets, providing reliable protection for various cycling activities. SOLID CONSTRUCTION: Features a durable polycarbonate outer shell bonded to an impact-absorbing EPS foam liner, offering strong protection without excess weight for comfortable wear during rides. READY TO RIDE: Designed with 18 wind tunnel vents and internal airflow channels to enhance ventilation and heat dissipation during extended use. ACCESSORIES: Includes removable and washable padding, and a detachable sun visor that helps shield the eyes from sunlight and protects against small debris. THREE SIZES AVAILABLE: Equipped with an adjustable rear dial system to customize the fit. Available in three sizes to suit most youth and adult head shapes for a secure and comfortable fit.