A facial sealing segment for a respiratory device includes a sealing flap adapted to sealingly engage the face of a user. The sealing flap is disposed about, and defines, a cutout adapted to receive one or both of the mouth or nares of the user. The facial sealing segment further includes a number of selectively removable portions formed in the sealing flap about the cutout. Each removable portion is defined in the sealing flap by a tear portion. The facial sealing segment may be customized by a method that includes removing at least one of the removable portions by separating the at least one removable portion from the remainder of the sealing flap by severing along the tear portion thereof.