Helmets are becoming an integral part of equipment for ski touring. As a rule, climbing helmets (EN 12492 certification) are used, which have excellent ventilation and are lightweight. Helmets with certification for skiing and snowboarding (EN 1077) are slightly heavier and have less (passive) ventilation. In order to take part in skialpinism races according to the international ISMF rules, the helmet must also meet the safety standards for skiing and mountaineering. Helmets are made of lightweight and durable plastic. The outer layer usually consists of polycarbonate, polypropylene (EPP) or ABS thermoplastic. The inner layer usually consists of polystyrene (EPS). Both layers are connected to one another by heat using in-mold technology. Ski helmets are usually available in two sizes. By turning a button on the back you can adjust the optimal head circumference. Ski-certified helmets usually have a layer of insulation and ear protection. Some helmets are equipped with a MIPS modification (Multi-Directional Impact Protection System) to improve brain protection.