Review on Versatile Cut-to-Fit Carbon Pad Pre-Filters for Air Purifiers, Furnace Filters, Trash Cans, and Air Conditioner Filters (1) by Kevin Lawson

Bought for $11 a year ago. Now it's $16. Considering this is a Covid related item the price increase seems reasonable. I used it as a pre-filter for an IQ air machine which also has a pre-filter that costs about 5 times this filter. This filter extends the life of the IQ filter. Now I trim the third and last filter I was able to cut off the roll. Every time I've changed it, the piece I took out of the car was almost completely covered in very fine dust. (see photo) I know it works, but how well does it work? I don't have any scientific measuring equipment, but after looking at the material I don't think it works as well as it could. The piece I received was made of a gauze-like material that was unevenly distributed. Some parts were thick, some were thin. (See the photo where I held it up to the light). It is clear that thick parts trap more dirt than thin ones. I may be wrong, but next time I'll try another product with evenly distributed material for comparison.