The main body waterproof design, the airflow can be regulation and step-less regulating airflow. There is a battery energy LCD and electronic warning system will buzz when Li-ion battery energy is low. Used for AC 100V—240V or DC 12V. Used for 1 people or used along with 2、3、4 people and each of hose can connect each other. Air supply distance achieved 120 meters single hose. Multi-helmets are suitable to PRF-104H main body which is suitable in many kinds of dust and gas working environment. Fully charged battery can be used for 7—20 hours continuously. Airflow: 120—280L/Min.