I highly recommend these filters. They work well and are easy to install. I have definitely noticed a reduction in my allergies since using these filters.
Two concerns, the pleats were widely spread apart in the middle while others bunched together at the boarder, rendering them useless. The filter will give me 60% of its designed efficiency.
Only place I could find the 4 nominal thickness that was actually less than 4 as I needed from my air handler. Got a MERV 13 rating to help with indoor air quality for a new born and a toddler. I come back every 18 months and buy 6 more now!! Thanks for making regular maintenance easier, I actually change my dog hair clogged filters now