The description says this has a HEPA filter yet once you order it the manual makes no mention of any filter at all. It also says in the description that this is good to use as a room deoderizer however in the manual it does not recommend this, instead suggesting it be used in a car (complete with pictures and instructions on placing it on the arm rest) or to use in the refridgerator! Not at all what I was looking for, however it does seem to work OK in a small enclosed room like a bathroom, it just takes long to have any impact.
It is small yet does feel well made, being maybe 4 inches tall and 2.5 inches across. It does not feel cheaply made or flimsy, having a metal shell with plastic top and bottom. There are 2 modes to use the purifier in, energy saving and boost. Energy saving will run the device for a short time using only the ion aspect that will make the room smell like the ozone from a thunderstorm then turn off for a while before starting again. It is quite a pleasant smell actually. Then there is boost mode where it will run continuously, drawing air from the small fan on the bottom through the unit (where the filter should be maybe?) and out the front along with the ion deorderizer. I honestly didn't notice much difference in air quality between the 2 modes so I leave mine on energy saving. It is rechargeable and will not run if plugged in, so this may be an issue for you, however it does allow it to be placed anywhere even if there is no outlet available. I can't say how long the battery last but with mine it did have a charge in it and I ran it for 3 days before deciding to plug it in, and even then it was still running strong.
The lack of the promised HEPA filter and difference in recommended uses is what keeps me from giving this a better score, and if I hadn't gotten this with a discount would have returned it for a full refund. However if you want to put this in your car and need special illustrated instructions on how to accomplish this then this is the item for you! Not worth the $22.99 asking price by any means but at $5 it's OK.