I ordered 16x40 and 20x40 air filters. The 16 and 20 inch dimension is 1/8 to 1/4 inch to large. I called three times and two e-mails later, well over two weeks, finally they agreed to refund my money.The problem is they only gave me a refund for the 16x40 filter, I am still waiting for the 20x40 filter. So far I emailed three times but no reply yet. As you can see in the photos the 20 inch side is to large. The customer service is way to slow if you have a problem.