DESC: 3-speed ambient air cleaner with patented "Air Flow Indicator" helps the customer determine when it's time to clean the filters. Includes free Electrostatic Filter. The dual filter system traps up to 99 percent of particles 1 micron in size. The blower provides 540, 830 or 1200 cfm, that filters the air in a 20 foot by 20 foot room between 13 and 18 times per hour. A remote control of the speed and timer settings. The time delay shut off can be set for up to 7-1/2 hours in 1/2 hour increments. The filter system consists of a 3-pocket inner filter and a pleated outer filter.