The Mirage Swift II is one of the quietest nasal masks on the market! Amazingly it is 86% quieter than the original Mirage Swift. In addition the Swift II's new vent design angles air downward in a direction more aligned with the natural flow of breath and less likely to interfere with the user or bed partners. Whether you sleep on your back or on your side the Swift II's four interchangeable tubing positions mean that you can angle the tube whichever way is best for you.