Review on Dakota Supplies TT MAC 2122 & TT MAC 2020 Installation: Expert Guide and Tips by Michael Hughes

Size as described and labeled otherwise looks as advertised. The item is not a true 4 inch as the description clearly states so be sure to measure your air conditioner's filter frame and do not rely on any other manufacturer's filter size. I ordered it knowing the dimensions and hoping it would fit my Lennox but it didn't. I used 3M Filtrete, 20x20x4 (which is actually closer to 4.25 +/-) and it was tight. I was hoping the Dakota brand would be a bit smaller and would fit, but it turned out to be too small. So I feel like Goldilocks. Not finding an "just right" I decided to just use a 1 inch filter and stop the whole escalation. In any case, this filter seems good, which is why I've given it four stars, subtracting one for the price.