Downhill certified ASTM polymer shell in three sizes 360° Turbine Technology Reduced peak brain acceleration by up to 30% at impact speeds associated with concussion Reduces peak brain rotational acceleration by up to 40% breakaway visor function for additional rotational impact force reduction Impact foam for superior energy absorption Premium washable inner liner for all-day comfort Optimal neck brace compatibility Certified and tested: AS/NZS 2063:2008, ASTM F1952–10, EN1078, CPSC 1203 Weight: 960 ± 50g (2.12 lbs) Sizing: XS (53-54cm – 20 ¾ - 21 ¼"), S (55-56cm – 21 - 22"), M (57-58cm – 22 ½ - 22 ¾"), L (59-60cm – 23 ¼ - 23"), XL (61-62cm – 24 – 24 ½"), XXL (63-64cm – 24 ¾ - 25")