A mask system for use in delivering breathable gas to a patient in positive airway pressure therapy, including: a cushion assembly (250) configured to receive a flow of the breathable gas pressurised above atmospheric pressure, the cushion assembly including a flexible plenum chamber and a seal forming portion (270) adapted to form a seal with at least a portion of the patient’s nose, the cushion assembly configured to in use attach to a headgear assembly with a two-point connection； and a decoupling system configured to in use isolate the cushion assembly from air conduit drag forces such that sealing forces applied by the cushion assembly to the patient’s face are not affected by the drag forces. The decoupling system includes a first decoupling structure comprising an elbow assembly, the elbow assembly (125, 128) configured to connect to an air conduit in use and an attachment region of the cushion assembly and permit the flow of the breathable gas into the cushion assembly, the elbow assembly configured to rotate about a plurality of axes relative to the attachment region, and a second decoupling structure (decoupling gusset 158(1)) that is configured to in use allow movement of the attachment region about a plurality of axes relative to the seal forming portion.
