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 PolyesterTechnology: IntegratedInternal 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: 18Certificate: CPSC 1203 + EN1078Package: 1*Mountain Bike Helmet, 1*User Manual, 1*Sun Visor, 2*ScrewsSAFETY 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 adventureSOLID CONSTRUCTION: Full Coverage Tough polycarbonate outer shell fusedhelmet'simpact-absorbing EPS foam layer for durability without excess weight, riding with free and comfortableREAD TO GO: Sleek design and diverse colors,it'scombined with 18 wind tunnel vents and internal channeling for heat dissipation during long journey ridingACCESSORIES: With washable and removable padding inside, a big visor for sunlight proof and protects the head from small objects3 SIZE AVAILABLE: The rear dial for customizing circumference with the easily adjustable system, with3 sizesavailableit fits most youth, adults, men, andwomen'shead sizes