My custom filters arrived promptly and fit perfectly. I think I even saved a little money buying them in bulk rather than buying them one-at-the time in the local hardware store.
The construction is just okay, usually there is one area that is not sealed.What is concerning is that after 10 days to 2 weeks, the filters starting putting off an unpleasant odor. Replacing the filter stops the odor but because these filters are custom made, replacing the filters so frequently is costly.