DescriptionFeature:1.High quality PC shell and lightweight EPS liner ensure durability and safety.2.With air vent for ventilate and cooling.3.Adjustable, suitable for most of people.4.Perfect for mountaineering, climbing, caving and other outdoor activities.Specification:Product: Rescue HelmetColor: Black,Blue,Yellow,Red,Hot PinkMaterial: PC(Poly Carbonate)+EPS(Expanded Polystyrene)Size: S M LHead circumference S: 48-56cmHead circumference M: 52-59cmHead circumference L: 54-62cmPackage included:1 x HelmetUsage:1.Adjust the length of the strap.2.Leave one finger space.3.Adjust the helmet to the right position.4.Check the buckle’s safety status.