View on LOZ Suggested Retail: $399. Health Oxygen Concentra Machine1-7 Liter for Home Use & Travel 110V. 5 layers of small molecule filtration. 24 hours uninterrupted work, without any safety hazards. The device is only 6.5kg, small size and lightweight. Its design is easy to move the machine. Suitable for home, travel and car use. The noise is less than 45 dB and will not affect sleep. with the cumulative time function, the total working time can be displayed on the display screen. There are also timing and remote control functions, which can operate the machine remotely, which is very convenient to use. The machine is equipped with a thermal protector and a one-key distress call function to better ensure the safety of the machine and people during use.. 7 CALENDAR DAY FULL REFUND GUARANTEE ON THIS ITEM IF ANY ISSUE IS FOUND THAT WAS NOT DESCRIBED/PICTURED. 7 CALENDAR DAY STORAGE IS ALSO AVAILABLE. SEE NOTES TO BIDDER, IN AUCTION DETAILS, AT THE TOP OF PAGE 1 FOR MORE INFO.