Oxygen masks are devices designed to deliver oxygen to individuals who may have difficulty breathing. They are commonly used in medical settings, such as hospitals and ambulances, as well as in aircraft during emergencies. The mask fits over the nose and mouth, allowing the user to inhale oxygen from a connected supply. In aviation, oxygen masks are crucial for pilots and passengers when flying at high altitudes, where the air pressure is lower and oxygen levels are reduced. These masks ensure that individuals receive adequate oxygen, helping to prevent hypoxia, a condition caused by insufficient oxygen in the body.