XTGOD Oxygen Concentrator_Machine_Compressor - Home Use_Air Purifier_1-5_Liter (Gold)

First,It does come with a very basic manuel, that describes all the functions. It is nice to have a reference.Second,It does work and concentrate oxygen. I was able to test the unit with an oxygen analyzer and the oxygen concentration is 90% at one liter per minute air flow and 70-80% at 3 liters per minute.Third,For it to be portable, you need to have a seperate battery pack. I purchased the ROCKPALS 300W Portable Generator Lithium Portable Power Station, 280Wh from Amazon. It will power it for almost 2.75 hours. The ROCKPALS is a very good independent power source. The ROCKPALS does come with a 12 volt cigarette adapter for the car.If you want to use the Oxygen Concentrator in your car to travel, you will need a 12 volt to 120 volt converter for your car's cigarette lighter. The unit has wall socket plug, thus you need the converter to plug it in. I did independently measured the power draw, it is not 90 watts as stated but draws 100 watts (if not using the anion generator). If your car cigarette power source can handle the amps, it should work just fine.I do like that it has a cleanable water humidifier, for dry weather. You can use the humidifier or not use it, it is optional.It is not heavy nor is it too bulkyI do like the set timer, but it can also be used continuously for 24 hour of use. It is not too loud, like a white sound machine set on medium loudness. the oxygen filter should last for 9000 hours of continuous use or so from what I have been able to figure out.It does come with a seperate anion generator: but the manual does not explain what it can do or the potential benefits:From WebMD"Negative ions are odorless, tasteless, and invisible molecules that we inhale in abundance in certain environments. Think mountains, waterfalls, and beaches. Once they reach our bloodstream, negative ions are believed to produce biochemical reactions that increase levels of the mood chemical serotonin, helping to alleviate depression, relieve stress, and boost our daytime energy"I do not know if the anion generator really works, but it is a free added functionI do not know if it works at higher altitudes above 8000 feet. It would be nice to know what the o2 concentration would work above 12,500 feet for those that would like to use it in small piston GA airplanes.Overall a really good purchase for a fraction of the cost of the other units on the market.it comes with an oxygen headset, but I would buy a separate nasal cannula

It works but no way to adjust it. It has buttons but don't know what they're for.