A nasal assembly for delivering breathable gas to a patient includes a frame having lateral connector, a cushion with a pair of nozzles, and a clip to secure the cushion to the frame. The frame includes a vent channel and a plurality of vent holes. The frame/cushion includes structure (lugs/cut outs) to prevent the assembly of an unvented frame with an unvented cushion, for safety purposes. The frame includes cored portions that interface with corner lugs provided on the cushion. A patient interface includes a frame, a cushion (nasal mask, nasal-oro mask, nozzles, etc.) and a vent assembly including a pattern of vent holes including at least two rows.