The Outlaw Style D.O.T Helmet Gives You that Great Look. The D.O.T. Helmet Contains the Following: (A) Metal Quick Release Buckle. (B)"Y" Strap Retention System for a Secure Fit. (C)Ply Fiberglass Shell with Hand Lamination. (D)Fully Lined Liner. (E) Steel Rivets.(G)This is a D.O.T Certified Helmet.......... Notes: Helmet Sizes:...Helmet Sizes: (Estimates).... Adult:.. Small Sizes are approximately 6-7/8-7.. Medium Sizes are approximately 7-1/8-7-1/4.. Large Helmet Sizes are approximately: 7-3/8-7-3/4.. Extra Large Sizes are 7-3/4 to 7-7/8..