Summary: What I like most about this product is the three speed option. I have one that I purchased 15 years ago and still love it ~ I not only use it to clear the air in my sons' room, but the humming noise helps them to sleep better. I purchased this additional Air Purifier so that our younger sons can also have their own. I am pleased with the three speeds as they offer several loudness control options. The filters are excellent and it works great.