XPOWER AP-2500D Air Purification System HEPA-300-PV Stage 3 V-Shaped HEPA FilterXPOWER Stage 3 HEPA Filter for XPOWER AP 2500D Filter Air Purification System Compatible with the XPOWER AP 2500D Portable HEPA Air Purification Systems, this 11. 5 inch. thick Professional HEPA Filter captures contaminants such as bacteria, allergens, mold, and even 0. 3 sized sub micron particles at a rate of 99. 97%. Several pre filter Air Scrubber stages ensure the long life of this filter. Replace as needed when the indicator light illuminates