Servicing, hyperbaric chamber is a steel, aluminum, or clear plastic room in which air can be compressed to a pressure that is greater than sea level. Most patients are treated at a pressure equivalent to two or/and a half times normal atmospheric pressure. It can be equipped with comfortable reclining chairs or stretch out to a completely flat position. To enhance patient comfort, music or movies can play during treatments, which are usually provided through a headset or an interior speaker. Whenever the chamber is in use, medical personnel trained in hyperbarics are in constant contact via visual or audio communications. A hypobaric chamber is a chamber used during aerospace or high terrestrial altitude research or training to simulate the effects of high altitude on the human body, especially hypoxia and hypobaria.