Positive airway pressure (PAP), commonly referred to as CPAP (which more accurately refers to the subset of “continuous” PAP devices), is the gold standard treatment for obstructive sleep apnea. PAP therapy applies air under positive pressure through the nose, mouth, or both, to prevent the collapse of the upper airway during sleep. This guide compares CPAP masks on parameters including warranty, available sizes, intentional leak, pressure range, and headgear. Information for this guide based on data submitted by PAP interface marketers. All PAP interface options may not be included.