Specifications Brand: AHP Material: ABS Weight: 450±50g Size:S M L XL XXL Quality certification: DOT Package Includes: 1 X Helmet 1X goggle 1X mask 1 X Cloth Bag Size S (55-56cm) M (57-58cm) L (59-60cm) XL (61-62cm) XXL (63-64cm) Features .One finger quick-release buckle! Smallest DOT shell size ever made. Meets D.O.T. FMVSS No.218 standards. Impact resistance ABS plastic 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.