About this item ★HIGH-IMPACT ABS Shell★—The Hard Shell Construction is Made of a Durable, High-Density, Injection Molded ABS Shell. ★For Multi-sports★—Skateboarding Scooter Roller Skate Inline Skating Rollerblading Longboard ★13 Strategically Placed Vents★—The Shell Has 13 Strategically Placed Vents. Each one Does Its Part to Exhaust Hot Air Out, and Bring Cold Air in, To Keep You Cooler & Drier During Those Long Sessions. ★Adjustable System&Strap★—Medium:20''-22.8'' (51cm-58cm); Large:21.3''-23.6'' (54cm-60cm).The Skateboarding Helmets Equipped with Adjustable System for Men/Women/Youth to Adjust Flexibly to Get a Better Fit. ★Great Protection★—This Helmet is a lightweight but excellent quality,these helmets would be the essential protective gear for any outdoor sports-lovers and have sizes for youth and adult.