ResMed Ultra Mirage™ Full Face CPAP Mask with Headgear stops the loss of air during CPAP therapy. Approximately 40% of CPAP users and practically all BIPAP users lose air pressure during treatment, either by mouth leak or mouth breathing. The loss of air pressure may potentially result in disrupted and uncomfortable sleep, compromising the effectiveness of the therapy and may even lead to flu-like symptoms. Fortunately, the Ultra Mirage Mask completely prevents the loss of air pressure thereby ensuring a positive and effective sleep apnea treatment. Comes in 6 convenient sizes: Small Standard, Small Shallow, Medium Standard, Medium Shallow, Large Standard, or Large Shallow.