The quality of the filter is excellent, however, they are excessively undersized. All filters are about 1/4 in. under the advertised size (industry standard) but these are a full 1/2 in + undersized which makes them leak or just not cover the opening completely without leaking. In my case, based on how they fit in my a/c unit measuring 20 x 24, they just arent large enough to properly fit. I will not be a returning customer until this situation is corrected.