A CPAP machine, or Continuous Positive Airway Pressure machine, is a medical device used primarily to treat obstructive sleep apnea. It works by delivering a steady stream of air through a mask that keeps the airway open during sleep, preventing interruptions in breathing. The machine consists of a motor, a hose, and a mask. The motor generates air pressure, which travels through the hose and into the mask worn over the nose or mouth. By maintaining an open airway, a CPAP machine helps improve sleep quality and reduces the risk of related health issues.