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 a patient's airways including at least entrance of the 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 structure that is shaped to be bisected by a sagittal plane that has a line that is tangent to the elastomeric seal-forming structure at a superior tangent point and at an inferior tangent point, wherein a first nasal bridge region of the elastomeric seal-forming structure straddles the sagittal plane in the vicinity of the superior tangent point, wherein a second nasal bridge region of the elastomeric seal-forming structure straddles the sagittal plane in the vicinity of the superior tangent point and is configured to seal against the patient's nasal bridge when the cushion is mounted on the patient's face, the second nasal bridge region having a thinner elastomeric wall than the first nasal bridge region, wherein a chin region of the elastomeric seal-forming structure straddles the sagittal plane and includes the inferior tangent point, the chin region being configured to engage the patient's chin when the cushion is mounted on the patient's face, the chin region having the same elastomeric wall thickness as the first nasal bridge region, and wherein a first support region and a second support region are positioned side by side and both extend from the chin region to the first nasal bridge region, the first support region having a consistent elastomeric wall thickness, and the second support region having a varied elastomeric wall thickness. 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 a patient's airways including at least entrance of the 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 structure that is shaped to be bisected by a sagittal plane that has a line that is tangent to the elastomeric seal-forming structure at a superior tangent point and at an inferior tangent point, wherein a first nasal bridge region of the elastomeric seal-forming structure straddles the sagittal plane in the vicinity of the superior tangent point, wherein a second nasal bridge region of the elastomeric seal-forming structure straddles the sagittal plane in the vicinity of the superior tangent point and is configured to seal against the patient's nasal bridge when the cushion is mounted on the patient's face, the second nasal bridge region having a thinner elastomeric wall than the first nasal bridge region, wherein a chin region of the elastomeric seal-forming structure straddles the sagittal plane and includes the inferior tangent point, the chin region being configured to engage the patient's chin when the cushion is mounted on the patient's face, the chin region having the same elastomeric wall thickness as the first nasal bridge region, and wherein a first support region and a second support region are positioned side by side and both extend from the chin region to the first nasal bridge region, the first support region having a consistent elastomeric wall thickness, and the second support region having a varied elastomeric wall thickness. an elastomeric seal-forming structure that is shaped to be bisected by a sagittal plane that has a line that is tangent to the elastomeric seal-forming structure at a superior tangent point and at an inferior tangent point, wherein a first nasal bridge region of the elastomeric seal-forming structure straddles the sagittal plane in the vicinity of the superior tangent point, wherein a second nasal bridge region of the elastomeric seal-forming structure straddles the sagittal plane in the vicinity of the superior tangent point and is configured to seal against the patient's nasal bridge when the cushion is mounted on the patient's face, the second nasal bridge region having a thinner elastomeric wall than the first nasal bridge region, wherein a chin region of the elastomeric seal-forming structure straddles the sagittal plane and includes the inferior tangent point, the chin region being configured to engage the patient's chin when the cushion is mounted on the patient's face, the chin region having the same elastomeric wall thickness as the first nasal bridge region, and wherein a first support region and a second support region are positioned side by side and both extend from the chin region to the first nasal bridge region, the first support region having a consistent elastomeric wall thickness, and the second support region having a varied elastomeric wall thickness.