One of the air returns in my home is just slightly smaller than a standard commercial filter so this one fits the bill. What is even better for me is that I was able to cut this one in half and each half fits perfectly, so I got a 2 for one! Works great especially with three cats in the house. First I use the vacuum for the obvious dust and hair, then I rinse it in the tub, shake it dry (gently) and put it back in. I clean my filters every other month and have had no problems at all.