The Proframe RS Helmet takes the lightweight breathability of the Proframe and takes it to the next level of safety and performance. Featuring the all-new MIPS Integra protection system, which combines an EPP liner with an EPS layer and is designed to reduce rotational forces in a crash otherwise transmitted to the brain. Designed to meet the needs of all-mountain riders and enduro racers, the increased ventilation and decreased surface contact of the helmet keep you cool on long rides, while the Ionic and anti-microbial liner and cheeks pads provide optimized comfort and fit. Fit is also assured care of the BOA fit system, offering class-leading fit and security, and the Fidlock magnetic closure system for easy-open and close use, even with gloves. The 3-position adjustable visor is compatible with goggles, and those looking to capture every sweet run will appreciate the removable, under-visor GoPro mount on the Fox Proframe RS mountain bike helmet. BOA fit system for class-leading fit and security MIPS Integra impact protection system combines an EPP liner with the EPS layer and is designed to reduce rotational forces in a crash 3-position adjustable visor compatible with goggles Removable under-visor GoPro mount included Increased ventilation and decreased surface contact area improve cooling Ionic+ anti-microbial liner and cheek pads to optimize fit Fidlock magnetic closure EPS, PC, PA, Epp, polyester CERTIFICATIONS ASTM F1952 (including chin bar rigidity test) N 1078 AS/NZ 2063 CPSC SIZE CHART - PROFRAME RS Note: The Helmet includes three spare sets of pads, in varying thicknesses, to adjust the fit. SIZE CM IN S 52cm - 56cm 20.5" - 22" M 56cm - 58cm 22" - 22.875" L 58cm - 61cm 22.875" - 24" XL 61cm - 64cm 24" - 25.25" Using a tape measure, measure the widest circumference around your head. Run the tape measure slightly above the eyebrows (typically ½” – 1”), keeping the tape measure horizontal and rounding the head above the ears. Take several measurements to ensure you have the largest circumference. Alternatively, you could use a string and measure it against a ruler. Apply your measurement to the helmet sizing chart to find your recommended helmet size. If a measurement falls in-between a size, go up to the larger size.