The Bell Alibi Youth Bike Helmet is constructed of an EPS foam layer bonded to a microshell using an inmold process, making the helmet both sturdy and solid. It's adjustable ErgoDial fit system, which can be operated with one hand, provides a snug and comfortable fit. The straps around the ears are easy to adjust with locking levers and the Pinchguard buckle that secures the helmet under the chin is specifically designed to prevent kids from pinching their necks. The helmet is equipped with a detachable, snap-in visor and 23 air vents. The colorful Alibi is a universal youth size, fitting heads from 19.75 to 22.5-inches (50 to 57-centimeters).