A patient interface system for delivering a flow of breathable gas to a user comprises a patient interface structure (5) configured to sealingly engage the face of the user, the patient interface structure comprising an aperture, and a connector assembly (10) comprising:- a ring (20) sealingly secured in the aperture of the patient interface structure, the ring including a first side configured to be in an interior of the patient interface structure and a second side configured to be at an exterior of the patient interface structure when the ring is secured in the aperture；- an elbow connector (40) secured in the ring, the connector having a first end and a second end, the second end being configured to be connected to an air delivery hose； and- a sleeve (30) provided between the ring and the elbow connector,wherein the ring comprises an inner flange (22) and an outer flange (23), the inner and outer flanges defining a channel (24) that is configured to sealingly engage the aperture of the patient interface structure；wherein the ring comprises a plurality of vent slots (25) that extend through the inner flange across the channel and through the outer flange of the ring； andwherein connection of the sleeve between the elbow connector and the ring provides a plurality of vents for venting of exhalation gases from the interior to the exterior of the patient interface structure.
