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