Patient interface

A patient interface for delivery of a supply of pressurised air or breathable gas to an entrance of a patient's airways for treatment of sleep disordered breathing, the patient interface comprising:

• a frame member including a main body and a pair of headgear connector arms extending from the main body;
• a cushion assembly provided to the frame member,
• wherein the cushion assembly includes a seal-forming structure constructed and arranged to form a seal with a patient's nose and/or mouth, and
• wherein the cushion assembly forms a void;
• headgear to maintain the patient interface in position on a patient's head, the headgear including a pair of headgear straps adapted to connect to a respective one of the pair of headgear connector arms of the frame member;
• and
• an anterior wall member repeatedly engageable with and disengageable from the frame member, the anterior wall member having a predetermined surface area to seal the void of the cushion assembly and form a gas chamber when the anterior wall member and the frame member are engaged,
• wherein the anterior wall member and the frame member are magnetically engageable, and
• wherein the void of the cushion assembly is sized such that the patient's nose and/or mouth is substantially exposed when the anterior wall member is disengaged from the frame member thereby improving breathing comfort of the patient.