This 3 layer filter works well to removes contaminants from the air. I've had my unit for over a year and I am amazed at the amount of dirt and micro particles this filter captures.A big plus is the outer blue filter can be washed or vacuumed which came in handy when we were doing remodeling and were able to wash that one filter which captures dust and larger particles and thereby not having to replace all 3 layers especially since the hepa filter was not dirty. This saves money.I like the different speeds although I had to reread the directions a couple times to figure out how to operate the various settings. When you feel you need extra filtering just turn it up, otherwise set to auto and it senses and detects the air quality and adjusts the speed automatically.With all the information about IAQ..indoor Air Quality and the EPA...Environmental Protection Agency reports on the effects that poor air quality has on people, we need to listen and learn from the scientists. I educated myself and was surprised at the amount of unhealthy and sometimes dangerous toxins in our interior air. Our carpets, our furniture, our pets and more add all kinds of impurities into our air. Life threatening, maybe not, but who knows the long term effects certain containments can have on us.We breathe all day and night and for me it's a no brainer to take a few important steps to ensure my family is breathing healthy air.Just wish I had been doing this years ago, but better late then never.I guess I got carried away with my review, sorry about that...I suppose you can tell I like the product...a lot.