The applicable groups of 3 liter oxygen generator and 5 liter oxygen generator are different

The 1-liter and 2-liter oxygen generators are suitable for the health-care oxygen inhalation for people with slight hypoxia, such as pregnant women with slight hypoxia, students who use their brains for a long time, white-collar workers, etc.
The 3-liter oxygen generator is suitable for people with mild to moderate respiratory diseases, cardiovascular and cerebrovascular diseases, and the third-highest level.
The 5 liter oxygen generator is suitable for: patients with severe diseases, people who need to use a ventilator, and those who need to inhale oxygen for a long time every day: patients with chronic obstructive pulmonary disease, pulmonary fibrosis, lung resection, lung cancer, pneumoconiosis, silicosis and other lung diseases.