The Hornit Lid is a well designed with fun decals to look stylish and fun, they are fully adjustable, comfortable, lightweight and actually something children will want to wear! Children and parents will love the integrated LED which is an added safety feature, useful for riding home after school all year round. Suitable For Cycling, Scootering, Skateboarding, Rollerskating And Rollerblading. Medium fits 55cm - 58 cm, safety tested to European standards. 11 air vents. LED has three modes with 10 hour run time. 5 hours constant, 10 hours flashing, requires 2x AG3 Batteries. Headband adjuster.