The beautifully designed Nutcase Gen 3 Helmet now features new sizing, improved ventilation, lighter weight, better reflectivity, detachable visor and removable spin dial. It has exterior crumble zones, an injection-molded ABS shell, fully padded interior and EPS foam liner. 11 strategically placed vents cool the entire head (2 front intake vents, 7 top-mounted exhaust vents, 2 back exhaust vents). Air channels in EPS also enhance ventilation while the optional visor protects your vision from sun and weather. Fidlock magnetic buckle gives easy, single-handed adjustment. The spin dial system offers a precision fit and 360 reflective details keep you visible in low light. Comes in 3 sizes so you can find the perfect fit. Small fits head sizes 20" - 22" (52cm - 56cm), Medium fits head sizes 22" - 23" (56cm - 60cm) and Large fits head sizes 23" - 25" (60cm - 64cm). Certified CPSC for Bicycle Riding and ASTM F1492 for Skating.