Austin Air Standard Healthmate HM400 Air Purifier B400B1, Black Everyday protection from indoor air pollutants with 4 stages of filtration True medical grade HEPA filter removes 99.97% of all particles larger than 0.3 microns and 4 stage filter protects against a wide range of indoor air pollutants such as dust, pet dander, pollen, and gases Over 780 cubic inches of activated carbon and zeolite filtration removes chemicals, gases and odors 3 speed settings for fan; 360 degree intake system draws air into all sides of unit, passing air through a 4 stage filter Reduces coughing, wheezing, sneezing, dry mouth, runny nose, snoring, and helps you sleep better; reduces night time allergies and asthma attacks; strengthens the immune system.