Prefilter, HEPA filtration for 99.9% particles down to 0.3 microns and Carbon Flitration for Noxious Vapors and Odors. Three speed operation, centrifugal fan. Baked on powder-coated all steel cabinet. Casters on large units for portability. 30-day money back guarantee. 5-year warranty on all products under normal residential use (5-year pro-rated filter guarantee).