"UNIT OF AIRCRAFT EMERGENCY OXYGEN SYSTEM FOR A PRESSURIZED CABIN,ACTIVATED WHEN CABIN PRESSURE DROPS BELOW A PRESSURE EQUIVALENT TO 13250 TO 14500 FT ALTITUDE THE CONTROL UNIT AUTOMATICALLY INITIATES AND CONTROLS THE FLOW OF OXYGEN FROM A HIGH PRESSURE SOURCE TO THE PASSENGER MASK COMPARTMENTS,CONTROL UNIT CAN BE MANUALLY ACTIVATED,RESET MANUALLY AT BELOW 12000 FT ALTITUDE,APPL BOEING 727 ACFT"