Review on 2-Pack FLT4825 True HEPA Filter B Replacement with Activated Carbon Pre-Filters for Guardian Air Purifier Models AC4825, AC4300, AC4800, AC4900, AC4850 by Derick Carpenter

Attached are photos comparing the manufacturer's original filter to the filter and pre-filters you get in this pack. The pre-filter has a denser mesh than the manufacturer's pre-filter. This has resulted in a restriction in airflow and my air purifier is not able to draw in enough air to filter it. That's the whole point. Whenever I've installed the original filter, I've noticed a difference within a minute (or less) of replacing the old filter. My air purifier is in front of the closet door where the litter box is, so the air purifier quickly gets rid of the smell of a fresh filter. When I put the filter included in this pack in (after having to press it in firmly at the top and bottom due to the added foam) I noticed a slight difference. It's been a few days and the air quality still hasn't improved and I doubt it will. I will buy OEM filters as I should, it will cost extra money.