A cushion for a patient interface device structured to deliver a flow of breathing gas to a user, comprising: a support wall portion; and a sealing flap extending inwardly from the support wall portion and toward a longitudinal axis of the cushion, the sealing flap having a distal edge which defines an opening in the sealing flap from a nose bridge to an upper lip, the sealing flap having an apex portion, a bottom portion located opposite the apex portion, a first side portion and a second side portion, wherein the bottom portion includes a first bottom section, a second bottom section and a third bottom section, wherein the second bottom section and the third bottom section each extend from the first bottom section toward the apex portion, wherein the first side portion extends from the second bottom section to a first side of the apex portion and the second side portion extends from the third bottom section to a second side of the apex portion, wherein the distal edge of the sealing flap includes a first point located at a middle of the apex portion, a second point located at a junction of the second bottom section and the first side portion, a third point located at a junction of the third bottom section and the second side portion, a fourth point located at a junction of the second bottom section and the first bottom section, and a fifth point located at a junction of the third bottom section and the first bottom section, wherein the first point, the second point and the third point lie in a first plane, wherein the second point, the third point, the fourth point, and the fifth point lie in a second plane, and wherein the first point lies in a third plane that is perpendicular to the longitudinal axis and the fourth point and the fifth point in a fourth plane that is parallel to the third plane, characterized in that an angle between the first plane and the second plane measured toward an interior of the cushion is greater than or equal to 105 degrees and less than or equal to 125 degrees, and in that the third plane and the fourth plane are separated by a distance that is greater than or equal to 15 mm and less than or equal to 30 mm. a support wall portion; and a sealing flap extending inwardly from the support wall portion and toward a longitudinal axis of the cushion, the sealing flap having a distal edge which defines an opening in the sealing flap from a nose bridge to an upper lip, the sealing flap having an apex portion, a bottom portion located opposite the apex portion, a first side portion and a second side portion, wherein the bottom portion includes a first bottom section, a second bottom section and a third bottom section, wherein the second bottom section and the third bottom section each extend from the first bottom section toward the apex portion, wherein the first side portion extends from the second bottom section to a first side of the apex portion and the second side portion extends from the third bottom section to a second side of the apex portion, wherein the distal edge of the sealing flap includes a first point located at a middle of the apex portion, a second point located at a junction of the second bottom section and the first side portion, a third point located at a junction of the third bottom section and the second side portion, a fourth point located at a junction of the second bottom section and the first bottom section, and a fifth point located at a junction of the third bottom section and the first bottom section, wherein the first point, the second point and the third point lie in a first plane, wherein the second point, the third point, the fourth point, and the fifth point lie in a second plane, and wherein the first point lies in a third plane that is perpendicular to the longitudinal axis and the fourth point and the fifth point in a fourth plane that is parallel to the third plane, characterized in that an angle between the first plane and the second plane measured toward an interior of the cushion is greater than or equal to 105 degrees and less than or equal to 125 degrees, and in that the third plane and the fourth plane are separated by a distance that is greater than or equal to 15 mm and less than or equal to 30 mm.