For tough trails you need a helmet that can last and that provides maximum coverage. The Bell Adult 4 Forty MIPS Bike Helmet has a lightweight Float Fit(TM) system for easy adjustments and 15 vents for breathability. Easily wear your goggles or glasses with the GoggleGuide(TM) adjustable visor. FEATURES: Designed for mountain biking Multi-Directional Impact Protection System reduces rotational forces from certain impacts and offers more protection Float Fit(TM) system is lightweight and has an easy-to-turn rubber overmolded dial for easy adjustments Ventilation: 15 vents Fusion in-mold polycarbonate shell with EPS foam liner provides strength and greater durability No-Twist Tr-Glides(TM) have quick-adjust fasteners that keep straps flat and positioned correctly GoggleGuide(TM) adjustable visor fits both glasses and goggles Sweat Guide(TM) pad pulls moisture away from the brow pad and eyewear Certifications: CPSC Bicycle and CE EN1078 Complies with U.S. CPSC Safety Standard for Bicycle Helmets for persons age 5 and older SIZING: S: 52 - 56cm M: 55 - 59cm L: 58 - 62cm XL: 61 - 65cm