The AirFit N20 is for anyone who wants a nasal mask that seals reliably without gripping the whole face. The InfinitySeal cushion sits over the nose (not in the nostrils, not over the mouth) and adapted to a wide range of facial shapes in a ResMed fitting study, with 99% of users achieving a successful fit.The cushion comes in Small, Medium, and Large, with the size printed on the cushion base; the frame itself is one size. A quick-release elbow with a dual 360-degree swivel keeps the short tube from dragging during the night, and magnetic headgear clips let you snap the mask on and off in two moves.The AirFit N20 works with any standard CPAP, APAP, or BiPAP hose. If you run it on a ResMed AirMini, you need the separate AirMini N20 setup pack since the standard short tube does not connect directly. A prescription is required to purchase this mask.