Adjustable headgear tubing for a patient interface

A positioning and stabilising structure configured to hold a cushion assembly of a patient interface in a therapeutically effective position on a head of a patient, the cushion assembly comprising a pair of plenum chamber inlet ports, the positioning and stabilising structure comprising:

• two gas delivery tubes, each of the two gas delivery tubes being connected at a first end to a corresponding one of the plenum chamber inlet ports to deliver a flow of air to the entrance to the patient's airways via the cushion assembly, each of the two gas delivery tubes being configured to be positioned on a corresponding lateral side of the patient's head in use, each of the two gas delivery tubes being constructed and arranged to contact, in use, at least a region of the patient's head superior to the otobasion superior on a corresponding lateral side of the patient's head, and each of the two gas delivery tubes comprising:
• a pair of tabs, each of the tabs projecting from a corresponding one of the two gas delivery tubes in a direction configured to be generally posterior relative to the patient's head in use, each of the tabs having a hole;
• a concertina portion configured to allow adjustment of a length of each of the two gas delivery tubes to fit different size heads, the concertina portion configured to be positioned, in use, superior to the patient's otobasion superior, and the concertina portion being configured to impart a biasing force along at least a part of the length of each of the two gas delivery tubes to urge the cushion assembly towards the patient's face in use;
• and
• a connection port configured to fluidly connect, in use, the gas delivery tubes with an air circuit to deliver the flow of air to the patient's airways, the connection port configured to be located, in use, superior to the patient's head, wherein the concertina portion is positioned on each of the two gas delivery tubes between the connection port and the first end, and
• wherein each of the tabs is positioned on a corresponding one of the gas delivery tubes between the concertina portion and the first end.