Patent ID: 8813748

Claim:
A mask assembly for delivery of a supply of gas to an entrance to the airways of a patient, said patient having a nasal bridge region, a cheek region and a chin region, said mask assembly comprising: a headstrap system to secure the mask assembly relative to the patient's head; and a cushion adapted to confront the face of the patient, said cushion comprising first and second membranes of integrally formed elastomeric material, each of said first and second membranes having an aperture adapted to receive the patient's nose and mouth, said second membrane defines a seal-forming portion on an outer surface thereof, said seal-forming portion being constructed and arranged to be positioned adjacent the nasal bridge region of the patient, along sides of the patient's nose, and below lips or on the chin of the patient to effect a seal, the seal forming portion is structured such that it is not required to turn in on itself to conform with the patient's face, said first membrane provides a supporting structure for the second membrane, said second membrane covering said first membrane, wherein the second membrane is substantially unsupported by the first membrane where the cushion is adapted to seal with the nasal bridge region in use.