Bell Alibi Youth Bike Helmet Sturdy helmet constructed of an EPS foam layer bonded with a microshell Adjustable ErgoDial fit system provides a snug and comfortable fit Straps around the ears are easy to adjust with locking levers Pinchguard buckle under chin specifically designed to prevent kids from pinching themselves Universal youth size fits 19.75 to 22.5-inches (50 to 57-centimeters)