"The Lock Down Fit System and the fitted liner of the CLH2 are designed to lacrosse's highest safety standards. The FreeFlow Cooling System with 13 vent holes provides maximum ventilation. The CLH2 has a customizable color system with individual injection molded visor and chin pieces available in a wide range of colors. Because the Cascade is a ""fitted"" helmet, measure the circumference of your head for sizing: 19 5/8"" to 20 1/2"" = XXS 20 5/8"" to 21 1/4"" = XS 21 1/2"" to 23 5/8"" = S/M 22 3/4"" to 24"" = M/L "