67812A/ 399389 HEPA Exhaust Filter (washable) for SC530A and SC535A Sanitaire Backpack Vacuums. The HEPA vacuum filters are designed according to strict HEPA standards. The media in these filters help trap 99.97% of all airborne pollutants 0.3 microns or larger, including mold spores, pet dander, grass and ragweed pollen and other microscopic allergens. Change filter every 90 to 120 days for optimum performance. Store filters in a clean, dry place. (replace part# 39938-8 and 39938-9)