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 and EPS Inner Buffer and Strap Polyester Technology: Integrated Internal Size: 1722cm(6.78.67in) Outside Size: 342219cm(13.388.677.48in) Weight: M-350g(0.77lb), L-380g(0.84lb), XL-390g(0.86lb) Vents: 18 Certificate: CPSC 1203 and EN1078 Package: 1Mountain Bike Helmet, 1User Manual, 1Sun Visor, 2Screws SAFETY FIRST: Our best-performance mountain bike helmet complies with U.S. CPSC E.U.CE Safety Stards for Bicycle Helmets, offering versatility sufficient protection to start your splendid adventure SOLID CONSTRUCTION: Full Coverage Tough polycarbonate outer shell fused\u00A0helmet's\u00A0impact-absorbing EPS foam layer for durability without excess weight, riding with free comfortable READ TO GO: Sleek design diverse colors,\u00A0it's\u00A0combined with 18 wind tunnel vents internal channeling for heat dissipation during long journey riding ACCESSORIES: With washable removable padding inside, a big visor for sunlight proof protects the head from small objects 3 SIZE AVAILABLE: The rear dial for customizing circumference with the easily adjustable system, with\u00A03 sizes\u00A0available\u00A0it fits most youth, adults, men, \u00A0women's\u00A0head sizes