Size Information: Infinity Seal Nasal Cushions come in three sizes -- Small, Medium & Large. All AirTouch N20, AirTouch N20 For Her, AirFit N20 and AirFit N20 For Her Masks use a single frame size so any UltraSoft or InfinitySeal Nasal cushion can be used with any N20 series mask frame. If you would like to change the size or style of your mask, you can just purchase a different N20 cushion and attach it to your existing mask frame.