The helmet is made from High Impact ABS Plastic, the Standard Material in the Helmet Industry.  Unique Features: High Impact ABS Shell provides for Great Energy Diffusion. Fabric Liner keeps the helmet fresh and reduces the "itch factor". The lining fabric is comfortable and can be disassembled and washed. Standard Features: Meets or exceeds D.O.T. FMVSS No.218 standards Ultra-Light Weight Design Weighs Less Than a Standard Bottle of Water! 1" Thick Polystyrene Protection Layer High Impact ABS Shell, provides for Great Energy Diffusion Fiberglass Shell with a High Impact for Superior Energy Diffusion  Quick Release Safety Strap for an Easy On and Off Experience Retractable Visors The half helmet is assembled with a built-in drop-down sun shield system and retracts with the flip of a switch. How to correctly measure your head: take a tape measure just above your eyebrow around your head just at the top of your ears. If your head measures in between sizes order the size smaller. Our helmets should fit snug when new, they stretch and mold to the shape of your head after short usage.