Replacement and only compatible with Mirage Quattro masks, they are not compatible with Quattro FX masks.
The Mirage Quattro uses four different frame sizes; therefore the ExtraSmall cushion/clip will only fit the ExtraSmall mask, the Small cushion/clip will only fit the Small mask, the Medium cushion/clip will only fit the Medium mask, and the Large cushion/clip will only fit the Large mask.