westinghouse air purifier true hepa filter replacement compatible with 1804 model (set of 4)

MEDICAL GRADE TRUE HEPA FILTER: The H13 medical grade True HEPA filters 99.97% of airborne pollutants, dust, pollen, and other allergens as small as 0.3 microns. LONG-LASTING AIR FILTER: All Westinghouse 1804 HEPA air filter replacements can be used up to 3,000 hours of operation; an indicator light on the unit will let you know when its time to replace; An indicator on the unit notifies you if the filter needs to be changed and also when youve installed the filter incorrectly EFFECTIVE AND SAFE: Trap dust mites, pollen, and other allergens with a True HEPA filter guaranteed to work effectively so you can breathe easy MODEL 1804 REPLACEMENT: This air purifier HEPA filter is a replacement for the Westinghouse air purifier with NCCO technology model 1804