FlexiFit™ Technology Auto-contouring fit With Foam or Air Cushion FlexiFit™ Technology automatically adjusts to a wide range of nasal and facial contours with simple one-step ease of fitting and no complicated adjustments. Glider Strap Anti-leak system The sliding Glider Strap provides freedom of movement while maintaining a seal. Mask force remains equal when the head rotates from side to side, minimizing the occurrence of leaks. Premium Frosted Silicone Seal Optimizing seal technology This seal technology has a soft, smooth feel to slide onto the face, and its frosted texture optimizes the mask seal. Stretchgear Headgear Deluxe mask suspension system This is a special elastic headgear segment that maintains an equal mask force when the head tilts up or down. Efficient Exhaust Quiet usage The advanced air diffuser system is quite, minimizing the noise and draft of the exhaust flow to prevent both sleeper and partner disturbance.* This mask is only effective when used in conjunction with a CPAP/BiLevel machine