For sale: 5-liter oxygen concentrator. Used twice. • - Higher than 90% medical oxygen concentration and better therapeutic effect for patients with pulmonary fibrosis. • The device is equipped with a humidifier bottle with a pressure relief valve for more comfort and ease of use. • Four flexible wheels for easy movement and positioning in any direction for more comfortable use. • - Oxygen flow rate from 0.5 liters to 5 liters. • Simple operation function and easy-to-read LCD screen. • There are alarms such as high and low pressure alarm, low oxygen generation alarm (power failure alarm - there are filters in the device (bacteria filter) - almost no sound, as the sound level is 38dbz) - • There is a HEPA filter & and a bacteria filter, and the device is very lightweight.