Kids helmet suitable for boys small children sizes 44 49 cm 46 51 cm 52 58 cm us sizes xs s m sm main colour blue number of air vents 8 safety features fly net reflective print safety light rear chin padding with chin pad inner padding removable size adjustments wheel adjustment system headring features chin buckle snap enhanced protection for back of head lower edge reinforcement construction co mold weight 220 g inner material polystyrene e