A cushion assembly for a patient interface for sealed delivery of a flow of air at a continuously positive pressure with respect to ambient air pressure to an entrance to the patient's airways including at least entrance of a patient's nares, wherein the patient interface is configured to maintain a therapy pressure in a range of about 4 cmH20 to about 30 cmH20 above ambient air pressure in use, throughout the patient's respiratory cycle, while the patient is sleeping, to ameliorate sleep disordered breathing, the cushion assembly comprising: an elastomeric seal-forming portion shaped to be bisected by a sagittal plane that includes a line tangent to the elastomeric seal-forming portion at a superior tangent point and an inferior tangent point, wherein the elastomeric seal-forming portion comprises: a dome-shaped superior region that straddles the sagittal plane in the vicinity of the superior tangent point, a saddle-shaped inferior region that straddles the sagittal plane and includes the inferior tangent point, a first support region extending from the saddle-shaped inferior region to the dome-shaped superior region, the first support region having a consistent elastomeric wall thickness that is greater than the elastomeric wall thickness of the dome-shaped superior region and the saddle-shaped inferior region, and a second support region adjacent the first support region that extends from the saddle-shaped inferior region to the dome- shaped superior region, the second support region being bounded by the first support region on a first side and having a second side opposite the first side, the elastomeric wall thickness in the second support region increases from the second side to the first side, the second side being closer to a central opening defined by a posterior side of the elastomeric seal-forming portion than the first side. an elastomeric seal-forming portion shaped to be bisected by a sagittal plane that includes a line tangent to the elastomeric seal-forming portion at a superior tangent point and an inferior tangent point, wherein the elastomeric seal-forming portion comprises: a dome-shaped superior region that straddles the sagittal plane in the vicinity of the superior tangent point, a saddle-shaped inferior region that straddles the sagittal plane and includes the inferior tangent point, a first support region extending from the saddle-shaped inferior region to the dome-shaped superior region, the first support region having a consistent elastomeric wall thickness that is greater than the elastomeric wall thickness of the dome-shaped superior region and the saddle-shaped inferior region, and a second support region adjacent the first support region that extends from the saddle-shaped inferior region to the dome- shaped superior region, the second support region being bounded by the first support region on a first side and having a second side opposite the first side, the elastomeric wall thickness in the second support region increases from the second side to the first side, the second side being closer to a central opening defined by a posterior side of the elastomeric seal-forming portion than the first side. a saddle-shaped inferior region that straddles the sagittal plane and includes the inferior tangent point, a first support region extending from the saddle-shaped inferior region to the dome-shaped superior region, the first support region having a consistent elastomeric wall thickness that is greater than the elastomeric wall thickness of the dome-shaped superior region and the saddle-shaped inferior region, and a second support region adjacent the first support region that extends from the saddle-shaped inferior region to the dome- shaped superior region, the second support region being bounded by the first support region on a first side and having a second side opposite the first side, the elastomeric wall thickness in the second support region increases from the second side to the first side, the second side being closer to a central opening defined by a posterior side of the elastomeric seal-forming portion than the first side.