Specifications: Head Size Fit: M for 54-57cm, L for 58-61cm Material: PC Shell and EPS Cushioning and Polyester Strap Technology: Integrated Molding Weight: M 360g, L 390g Vent: 17 Certificate: CE EN 1078 and CPSC cfr1203 and NTA-8776 Outside Size: 32 x 21 x 19cm Internal Size: 20.5 x 17.5cm ​ SAFETY FIRST: Combined with impact-resistant materials and reliable helmet design solutions, a solid structure is made to maximize head safety and provide sufficient cycling protection, complies with certification NTA-8776 Helmets for S-EPAC riders, US CPSC and EU CE Safety Standards for Bicycle Helmets SOLID CONSTRUCTION: The Tough polycarbonate outer shell fused helmet's impact-absorbing EPS foam layer for durability without excess weight, riding with free and comfortable READ TO GO: Sleek design and diverse colors, it's combined with 17 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, the visor can be fixed in 3 angles whether you prefer to increase visual range or take extra cover 2 SIZE AVAILABLE: The rear dial for customizing circumference with the easily adjustable system, with 2 sizes available (Medium for 54-57cm/21.25-22.44in, Large for 58-62cm/22.83-24.4in) it fits most youth, adults, men, and women's head sizes