Triple Eight Sweatsaver Liner Helmet is a classic helmet designed for skateboarding and roller skating. The design incorporates an ABS outer shell with a stink-free, moisture-wicking Sweatsaver liner inside. Adjustable chin strap ensures a comfortable fit. Sweatsaver liner is easily-removable for cleaning; wash gently by hand and air dry. The Triple Eight Sweatsaver Helmet is available in five sizes: Small fits 20.6–21.3 in (52–54 cm), Medium fits 21.4–22 in (54–56 cm), Large fits 22.1–22.9 in (56–58 cm), X-Large fits 23–24 in (58–61 cm), XX-Large fits 24-25 in (60–62 cm). To determine proper size, measure with a soft tape measure or string. Expect to wear for a couple of hours before the helmet is completely broken in. This product is NON-CERTIFIED and is NOT intended for use as a bicycle helmet. This product has NOT been tested under CPSC, ASTM, or CE safety standards.