This BLUE Gel Nasal Cushion features a new generation, soft, pliable gel that readily adapts to facial features, thereby simplifying fit and contributing to overall comfort. The included Secure Seal Technology (SST) Comfort Flap fits over the gel cushion to improve overall seal and help extend cushion life. COMPATIBILITY: BLUE Gel Nasal Cushions and SST Comfort Flaps are supplied with all ComfortGel BLUE Nasal CPAP Masks. They are also compatible with ComfortGel "Original" NASAL Masks.