Replacement Filter for the Austin Allergy Machine HEPA and military carbon cloth unit 13.5" diameterl 14.5" height 60 sq. ft. true HEPA medical filter medium Strategically placed military carbon cloth Meets HEPA standards, trapping 99.97% of all particulates larger than 0.3 microns Foam sealing gaskets top and bottom Total weight 13 lbs PERMAFILT Prefilter Traps large dust particles Designed to be vacuumed from outside and eliminate costly 3 month filter changes. Pre-filter is included.