This cushion from Respironics is designed for use with all Wisp Masks. Four cushion sizes -- Petite, Small Medium, Large & Extra Large -- are available. The Wisp's hybrid cushion design was created by combining the comfort of a mask with the minimalism and seal of a pillow mask. Any cushion size will fit on any Wisp the mask frame so if you find you want to try a different size you can simply purchase a new cushion rather than having to buy a whole new mask. AVAILABLE SIZE (S)Petite, Small Medium, Large, Extra Large MATERIALS is Not Made with Natural Rubber Latex Respironics Cushion for Wisp Masks.