Filterbuy 20x20x4 Air Filter MERV 13 Smoke Defense, Pleated HVAC AC Furnace Filter Replacement, 2-Pack

Very high MERV; much higher than most other filters. It measures exactly as it is specified in the details - less than 4 inches in width. Many "4 inch" width filters are actually 4.25 or 4.4 inches, so they do not fit my filter box. Good and sturdy quality!

I placed this on a 20x20 box fan and sealed the sides with duct tape to act as a large air purifier for secondhand smoke. It seems to be working well.

IT WAS JUST AS EASY TO INSTALL AS OTHER FILTERS.

Loved the product it does the job

This worked perfectly for my needs. I used it as a part of a filtration system for my workshop.

Easy to install and works great

Great deal on these filters. We have three rescue cats, one of which I am allergic to. I've noticed less issues since switching to this brand. I change my filters every 45-60 days and noticed the filter went in bright blue and came out a medium gray color.

I purchased 4 of these last year but didn't create an acct. I didn't pay close attention but I thought the pleats were evenly spaced. These, that I purchased this year are not. The one that measured range from a1/2" to 1-1/2'. and they are placed in the frame crooked. I have an old flip phone and cannot provide you with pictures nor video. otherwise, a GREAT filter!!

I know they are not 3M brand, however, they seem to work just well . . . . . . . . the size is perfect and they fit well. . . . they are a quality item and I know that because there is a smoker in my home and they help greatly clearing the house of smoke and it's awful left behind odor!

The shipping was quick. The filter seems to be working well. With two old shedding pugs, the air in my house needs all the help it can get. My allergies seem to be better. If they really do last 3 months, then this was a fantastic buy. Only time will tell.