Valiant II Blackout Modular Mindy Kaling Swears By This Food Hack For Her Daughter. SPECIFICATIONS Ultra light, strong yet flexible shell using LS2s proprietary Kinetic Polymer Alloy (KPA) Twin Shield System drop down sunshield is operated by a cable slider for smooth and dependable sun protection Chin bar flips 180 degrees allowing the rider to easily swap between a full face or open face helmet Removable, washable Thermo Form comfort padding is made of a breathable fabric that wicks moisture and dries quickly keeping the rider cool and comfortable Meets or exceeds DOT FMVSS 218 standards HELMET SIZING Measuring your head for helmet fitment is the right place to start, but it is only a guideline. Different shapes of heads might require a slightly smaller or larger helmet in any given model. Trying on the model you are interested in is always recommended. A helmet should be as snug as possible, without being so tight that it will give you a headache. Its best to be fitted by a professional. Size Centimeters Inches X Small 53 54 cm 20 7 8 21 1 4 Small 55 56 cm 21 5 8 22 7 8 Medium 57 58 cm 22 1 2 22 7 8 Large 59 60 cm 23 1 4 23 5 8 X Large 61 62 cm 24 24 3 8 2X Large 63 64 cm 24 3 4 25 1 4 3X Large 64 65 cm 25 5 8 26 4X Large 66 67 cm 26 3 8 26 3 4