A safe breathing atmosphere can be achieved with the aid of a supply air respiratory system (SAR). SARs provide air when oxygen levels in the environment are low or air quality is compromised. With Allegro's complete full mask system, workers can have portable, lightweight air sources that meet the requirements of one, two, or three workers at the same time. As a matter of fact, the capacity of an air compressor can be unlimited, while the mobility of an airline worker is limited. Several factors need to be taken into consideration by the wearer of a SAR (supplied-air respirator). Among the components that make up these systems include a breathing tube, a hose, and a respirator, to name a few.