V-Share Adult Ajustable Bike helmet with Snap on/off visor in Black Use ONE STEP technical material, EPS increases impact resistance of composite materials Ultra-light, wind tunnel, duct design, effectively reduce wind resistance. High-quality foam layer, the adjustment within the twist, you can adjust the size of head circumference. Suitable for people with head circumference 56-63cm and the head-width below 17.5cm. 18 flow vents to keep you cool with snap on/off visor for sun protection