Bell Trigger Youth Bike Helmet Entry-level, youth bicycle helmet perfect for cruising and recreational touring Universal size fits head circumferences of 54 to 61 centimeters / 21.25 to 24 inches Durable and protective Fusion In-Mold construction with 23 cooling air vents ErgoDial fit system and Cam-lock levers for simple size adjustments; PinchGuard buckle CE EN1078, CPSC bicycle certified; one year warranty