The helmet has multiple ventilation holes, suitable for participating in training, search and rescue operations, and is a necessary helmet for rock climbing or other outdoor sports. The inside of the helmet is lightweight and impact resistant. The ventilation and other functions of the EPP air cushion and the EPP air cushion will not cause damage to the ambient temperature, altitude and humidity. The material is ABS. ABS resin is one of the five synthetic resins with impact resistance, heat resistance and low temperature resistance. There is no size for the head circumference, suitable for most people, available for men and women.