This is a single replacement cushion for use with the ResMed AirFit F10.
Frame and Cushion Size Compatibility: This cushion is available in size X-Small, Small, Medium and Large. All size cushions do NOT fit on all size frames. See below for details on size compatibility.
ResMed AirFit F10: There are two frame sizes for the AirFit F10: size XS/S and size M/L. Size extra small and small AirFit F10 cushions fit on the XS/S frame. Size medium and large AirFit F10 cushions fit on the M/L frame. A size small cushion is NOT compatible with a size M/L frame and vice versa.