Giro Radix MIPS MTB Helmet - Matt Trail Green Integrated MIPS Technology: Reduces rotational forces that may be transferred to rider's brain in certain impacts Deep Coverage: Designed for maximum protection in the back P.O.V. Visor: Offers 15 degrees of adjustment Cool-fit anti-Microbial padding Construction: Full-wrap In-Mold polycarbonate shell with EPS liner Fit System: Roc Loc 5.5 MIPS: Allows you to customize fit/feel for enhanced stability and long range comfort Ventilation: 25 Wind Tunnel vents with internal channeling Sizing: Small (20-21.75", 51-55cm); Medium ( 21.75-23.25", 55-59cm); Large (23.25-24.75", 59-63cm); X Large (24-25.5", 61-65cm) Certification: Complies with the U.S. CPSC Safety Standard for Bicycle Helmet for Persons Age 5 and Older