A mask and a vent assembly therefor

摘要

The present invention relates to a system for supplying breathable gas pressurized above atmospheric pressure to a human or animal's airways. The system comprises a mask (10), a rim (28) bounding an opening (26), and a vent assembly (20) for gas washout. The vent assembly is configured to be retained in the opening. At least one of the vent assembly and a region surrounding the opening has a flexibility allowing the vent assembly to be squeezed through the opening before engaging the rim.