A sensor is provided for monitoring air pressure, with the sensor issuing a pressure detection signal that is greater or lower than a preferred range of air pressure for {HEAD ~ air flow} transmitted to {TAIL ~ the mask} 
transmitted to
A sensor is provided for monitoring air pressure , with the sensor issuing a pressure detection signal that is greater or lower than a preferred range of air pressure for { HEAD ~ air flow } transmitted to { TAIL ~ the mask }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL