The Mavic Aksium Elite Cycling Helmet will keep you protected on the commute into work, breeze through a weekend ride and stay comfortable on longer trips.Ergo Hold SL Retention System, delivers an optimal adjustability, comfort and head hold Aksium Elite Fit Pad offers exceptional comfort thanks to progressive padding and shaped design Anti-mosquito mesh for increased safety during the ride 3 position adjustment system Reflective highlights Weight: 5. 5 oz. (size M) Sizes : S/20-22"; M/21 ? - 23 ?"; L/22 ? - 24 inches"