The QuFresh Air Scrubber HEPA Filter is the third and last filtration step for the QuFresh air scrubber, filtering particles down to 0.3 microns in size with 99.97% efficiency from your indoor space. This replacement filter is a perfect fit for QuFresh model AS1000WHT and has an H13 rating for capturing even the smallest common airborne pollutants. Installs easily into the air scrubber by simply opening the unit's latching front cover and removing the internal brackets with common household tools. To keep your air scrubber operating at peak performance, replace this filter when "change HEPA filter" indicator light on scrubber unit illuminates.