Adjustable headgear tubing for a patient interface

A positioning and stabilising structure to hold a seal-forming structure in a therapeutically effective position on a head of a patient, the seal-forming structure being constructed and arranged to form a seal with a region of the patient's face surrounding an entrance to the patient's airways for sealed delivery of a flow of air at a therapeutic pressure of at least 4 cmH2O with respect to ambient air pressure throughout the patient's respiratory cycle in use, the positioning and stabilising structure comprising:

• a front hoop extending, in use, across the patient's cheek regions and arranged to contact, in use, regions of the patient's head superior to an otobasion superior of the patient's head, the front hoop comprising:
• lower portions of two gas delivery tubes fluidly connected to the seal-forming structure, each lower portion of the gas delivery tube extending, in use, across one of the patient's cheek regions, the two gas delivery tubes being on different sides of the patient's head, and
• a link connecting the two gas delivery tubes between the lower portions and upper portions of the two gas delivery tubes;
• and
• a rear strap configured, in use, to pass around the back of the patient's head;
• a de-coupling mechanism configured to decouple positional adjustment of the upper portions of the gas delivery tubes from movement of the seal-forming structure away from the patient's face in use to enable positional adjustment of the upper portions of the gas delivery tubes on the patient's head;
• and
• an adjustment mechanism configured to adjust the front hoop and the rear strap relative to the patient's head, the adjustment mechanism being arranged in a single operation to adjust both the front hoop and the rear strap to enable the positioning and stabilising structure to fit different size heads.