Oxygen breathing apparatus is also called isolated compressed oxygen breathing apparatus.The respiratory system is isolated from the outside world. The instrument and the human respiratory system form an internal circulation. Oxygen is provided by a high-pressure gas cylinder. There is an airbag to store the gas during exhalation and inhalation. This product has stable and reliable performance and is widely used in petroleum, chemical, metallurgy, coal, and mining. , Laboratories and other industries (departments), for use by specially trained persons in toxic and harmful gas environments (normal atmospheric pressure) for emergency, accident management, rescue or operation.