A self contained breathing apparatus, or SCBA, sometimes referred to as a Compressed Air Breathing Apparatus (CABA), air pack, or simply Breathing Apparatus (BA) is a device worn by rescue workers, firefighters, and others to provide breathable air if the max use concentration for the APR is exceeded, the air concnetration is unknow, or there is ann an IDLH (Immediate Danger to Life and Health) Atmosphere. <BR>An SCBA typically has three main components: a high-pressure tank (e.g., 2200 psi to 4500 psi), a pressure regulator, and an inhalation connection (mouthpiece, mouth mask or face mask), connected together and mounted to a carrying frame.<BR>National Institute for Occupational Safety and Health<BR>