System for delivering breathing gas to passengers

A system for delivering breathing gas to passengers, the system comprising:

• a face mask comprising a face part having a breathing cavity;
• a tube configured to be supplied by pressurized breathing gas;
• and
• a reservoir bag disposed between the tube and the face part, wherein a passage connects the reservoir bag to the breathing cavity so that the system is configured to supply the breathing cavity through the reservoir bag, wherein the reservoir bag comprises a front portion and a back portion, wherein the front portion is connected to the face mask,
• wherein the system has a stowed configuration and a deployed configuration, wherein in the stowed configuration, the reservoir bag is maintained folded between a backing and the face part,
• wherein the back portion comprises a protrusion, and wherein, in the stowed configuration, the protrusion is releasably retained by the face part to maintain the reservoir bag folded between the back portion and the face part.