You gotta keep that bucket safe! Grab the Brainsaver Helmet and head out! ; Complies with U.S. CPSC Safety Standard for Bicycle Helmets for persons age 5 and older and ASTM F-1492-08 Safety Standards for skateboarding and trick roller skating. ; Polystyrene liner helps cushion the blow. ; Classic skate, side-cut helmet is super sleek and lightweight. ; Great for protection while participating in a variety of action sports, including biking, skateboarding, snowboarding, and roller derby! Head Sizes: Measure the circumference of your head starting in the middle of your forehead, and match it with the sizes below. ; Each helmet comes with 2 liners to accommodate both sizes. ; XS/SM: 18.9-21.3 in ; SM/MD: 21.7-22.8 in ; LG/XL: 23.2-24 in ; This product may have a manufacturer's warranty. Please visit the manufacturer's website or contact us at for full manufacturer warranty details.