Breathing assistance apparatus

An assembly for use as part of an apparatus for supplying a flow of respiratory gases to a user, comprising:

• an internal cavity bounded by a mask body and a mask seal assembly, the mask body comprising:
• an inlet configured to allow respiratory gases to flow into the internal cavity,
• a wall extending rearwardly toward a user in use, and
• vent holes configured to allow expired respiratory gases to vent from the internal cavity,
• at least one headgear extension extending from the mask body and configured for removable connection to a headgear;
• the mask seal assembly comprising a mask seal and a mask seal clip;
• the mask seal having a clip side shaped for attachment to the mask seal clip and a face side configured to abut and substantially seal against contours of the user's face such that the internal cavity can maintain positive gas pressure;
• the mask seal clip extending around substantially a full perimeter of the mask seal assembly and configured to releasably attach to the mask body;
• the mask seal comprising a first silicone material and the mask seal clip comprising a second silicone material with a higher shore hardness than the first silicone material such that the mask seal clip is more rigid than the face side of the mask seal,
• the mask seal assembly further comprising a sealing lip extending transverse to the rearwardly-extending mask body wall such that, when the mask seal assembly is releasably attached to the mask body, the sealing lip bears against, thereby tilting from transverse contact with, a rearward-facing end of the wall.