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 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 EN1078 Package: 1Mountain Bike Helmet, 1User Manual, 1Sun Visor, 2Screws SAFETY FIRST: Our best-performance mountain bike helmet complies with U.S. CPSC and E.U.CE Safety Standards for Bicycle Helmets, offering versatility and sufficient protection to start your splendid adventure SOLID CONSTRUCTION: Full Coverage Tough polycarbonate outer shell fusedhelmet'simpact-absorbing EPS foam layer for durability without excess weight, riding with free and comfortable READ TO GO: Sleek design and diverse colors,it'scombined with 18 wind tunnel vents and internal channeling for heat dissipation during long journey riding ACCESSORIES: With washable and removable padding inside, a big visor for sunlight proof and protects the head from small objects 3 SIZE AVAILABLE: The rear dial for customizing circumference with the easily adjustable system, with3 sizesavailableit fits most youth, adults, men, andwomen'shead sizes