<b> Helmet Size Chart</b> <br> <br> S 49-50 CM 18.9/19.3 Inch <br> M 51-52 CM 19.7/20.3 Inch <br> L 53-54 CM 20.7/21.1 Inch <br> <b> Helmet Size Tips</b> <br> <br>(1)Wrap a measuring tape around your head about a half-inch above eyebrows <br>(2)Take measurement two to three times to pick the largest one.