The green light is on when the oxygen purity is at least 87%. The yellow light turns on when the oxygen purity is between 95 and 87 percent. It has an input power of 400 VA, AC120V±10 voltage power, and an operational pressure relief mechanism of 250kPa±25kPa which can be used to treat respiratory, cardiovascular, and cerebral vascular problems as well as chronic obstructive pulmonary disease, carbon monoxide poisoning, and other hypoxia-related ailments.