The Opus Nasal Pillows Mask without headgear includes all mask components except the headgear. The Opus™ Nasal Pillows Mask is small, quiet and superbly comfortable with an anatomical pillow-style silicone seal, and facially contoured headgear with reinforcement for extra stability. The ball-and-socket-styled joint combines with the innovative anchoring system to give unprecedented stability and freedom of movement. Includes Small, Medium and Large size nasal pillows.