Product review (5 stars): Little hard to install, but work great
Mine are a little hard to put into my Moist Air HDC-12.  The filter holders have a slight curve, and the filters are obviously not curved.

Still, they wick up wonderfully IF...you remember to use mold and fungus inhibitor.  Otherwise, the bottoms will blacken and they will not wick up properly, plus they will put out odors and possibly mold spores.