A headgear for use with a respiratory mask, comprising: a back panel having a trapezoidal shape comprising a top edge, a bottom edge and lateral edges that connect the top edge to the bottom edge, the back panel formed from two layers of 3D fabric folded from a sheet of 3D fabric to have a folded edge , the folded edge forming the bottom edge of the back panel , having a first width W 1 , which extends across the back of a user's neck in use, a sewn edge forming the top edge of the back panel , having a second width W 2 , the first width W 1 being less than the second width W 2 , the sewn edge having a seam allowance having free ends extending radially inwardly within the interior of the back panel , the lateral edges of the back panel being linear towards the folded edge and convex towards the sewn edge , the distance between the lateral edges of the convex region defining a third width W 3 , which is the widest point of the back panel , and the corners of the free ends of the seam allowance defining a fourth width W 4 , the fourth width W 4 being less than the third width W 3 such that the seam allowance does not extend beyond the lateral edges of the back panel ; and perimeter portions , formed from a foam laminate material, stitched to the respective lateral edges of the back panel along a join. a back panel having a trapezoidal shape comprising a top edge, a bottom edge and lateral edges that connect the top edge to the bottom edge, the back panel formed from two layers of 3D fabric folded from a sheet of 3D fabric to have a folded edge , the folded edge forming the bottom edge of the back panel , having a first width W 1 , which extends across the back of a user's neck in use, a sewn edge forming the top edge of the back panel , having a second width W 2 , the first width W 1 being less than the second width W 2 , the sewn edge having a seam allowance having free ends extending radially inwardly within the interior of the back panel , the lateral edges of the back panel being linear towards the folded edge and convex towards the sewn edge , the distance between the lateral edges of the convex region defining a third width W 3 , which is the widest point of the back panel , and the corners of the free ends of the seam allowance defining a fourth width W 4 , the fourth width W 4 being less than the third width W 3 such that the seam allowance does not extend beyond the lateral edges of the back panel ; and the back panel formed from two layers of 3D fabric folded from a sheet of 3D fabric to have a folded edge , the folded edge forming the bottom edge of the back panel , having a first width W 1 , which extends across the back of a user's neck in use, a sewn edge forming the top edge of the back panel , having a second width W 2 , the first width W 1 being less than the second width W 2 , the sewn edge having a seam allowance having free ends extending radially inwardly within the interior of the back panel , the lateral edges of the back panel being linear towards the folded edge and convex towards the sewn edge , the distance between the lateral edges of the convex region defining a third width W 3 , which is the widest point of the back panel , and the corners of the free ends of the seam allowance defining a fourth width W 4 , the fourth width W 4 being less than the third width W 3 such that the seam allowance does not extend beyond the lateral edges of the back panel ; and the distance between the lateral edges of the convex region defining a third width W 3 , which is the widest point of the back panel , and the corners of the free ends of the seam allowance defining a fourth width W 4 , the fourth width W 4 being less than the third width W 3 such that the seam allowance does not extend beyond the lateral edges of the back panel ; and perimeter portions , formed from a foam laminate material, stitched to the respective lateral edges of the back panel along a join. <EOS>