Liberty HEPA-Air Cleaner delivers Pure Air. 99.99% efficient in removing air-borne contaminants. All metal housing and non varnished motor windings eliminate toxic out gassing. 400 C.F.M. will give up to 20 air changes per hour in the average size office or bedroom. Air flow design allows only clean air back into the room. 3 speed high efficiency motor is noiseless and costs pennies a day to operate. One year warranty. 80 square feet of HEPA and 15 lbs. of activated charcoal + zeolite eliminate 99.99% of particles down to 0.3 micron and over 200 toxic chemicals found in homes and offices.