The Jetro has a 3/4 construction with a distinctive Vanguard-inspired design and provides full protection for the back of the head.the Jetro's design is engineered to exceed NTA (speed electric bike certification) and crash testing standards such as MIPS and Virginia Tech Protocol, where it is rated the safest MTB helmet.a stable, comfortable and safe helmet that combines cutting-edge technology with elegant design. Polycarbonate shell with EPS liner. Five-star Virginia Tech Helmet Lab Rating NTA 8776 Certified Extended coverage for the back of the head and jawline Magnetic Fidlock® buckle makes helmet fitting easy Cheek pads designed to help achieve a perfect fit. The Safe-T Heta 360° headband attachment system and 3 vertical adjustments give you everything you need to find a uniquely individual fit. 21 air vents, designed with an air conduction system that improves ventilation and comfort Comfort pads are hand washable, improving hygiene and extending the product's lifespan With a wide field of vision, it is compatible with all glasses and sunglasses Includes a soft storage bag S M L A (cm) 52/56 56/58 58/61 Weight (g) 570 595 660