The Saw Style Punk Spike Novelty Helmet Gives You that Great Look. The Spike Punk Novelty Helmet Contains the Following: (A) Metal Quick Release Buckle. (B)"Y" Strap Retention System for a Secure Fit.(C)Fully Lined Liner. (D) 3/4 and 1 Inch Saw Strip Chrome Spikes. (G)This is NOT A D.O.T Certified Helmet. Saw Punk Spike Novelty 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..