While I always try for and appreciate US made products I will have to look elsewhere for my next ac filters. All the previous filters I have used for the 35 years Ive owned this house are only 1/4 inch smaller than the displayed dimensions on the filter. With your 1/2 inch smaller than displayed dimensions your filter allowed a corner and 2 sides to bypass the mounting flange and the filter to start entering the return air duct. Wish you the best but I will have to take my business elsewhere. Richard Bunnell