No.66 TOWN Adults Lightweight Road Mountain Cycling Bike Helmets Safety:shell made with high quality 0.8 mm PC ,Sturdy ;and with high density 85% EPS,shockproof well Integral forming process technology,seamless connection,durable and nice Comfortable:streamlined design, anti-windage, lightweight,adjustable Chin Strap with Quick-Release Buckle, sweat chin pad,with visor 18 ventilation hole,breathable;protective pad liner,better to protect head;removable protective pad liner,more easy to clean Light weight:0.5 lb;Helmet Size:about 10 x 9 x 5.5 inchs;Head circumference:about 22-25 inchs ,adjustable