Patent ID: 8839789

Claim:
A respiratory patient interface assembly for use in delivery of non-invasive positive airway pressure to a user comprising: a rigid patient interface shell including an inner wall and a plurality of slots; a soft cushion including a seal-forming membrane structured to form a seal with the user's face and at least one flexible sealing lip constructed and arranged to extend radially inward beyond the inner wall from an inner periphery of the cushion and to deform to provide a continuous airtight seal between the cushion and the rigid patient interface shell, the at least one flexible sealing lip being further constructed and arranged to return to a relaxed state when the cushion is disassembled from the rigid patient interface shell; and a retaining ring coupled to the cushion, and including a plurality of clips each positioned on respective spring arms to engage with each of the respective plurality of slots of the rigid patient interface shell to retain the cushion in position with the rigid patient interface shell in use.