I had never heard of the brand, Instant, before, but I decided to give them a try with this air purifier. I got the small one, and it is very compact and unobtrusive. It is easy to find a place for it and it runs very smoothly with only a quiet hum. I wasn't sure if I'd be able to tell the difference, even in a small room, but the room actually smelled better after a day. When I cleaned the filter, there was so much filth! I can't believe that was all in the air!