Product review (4 stars): Got Mine Today, Measures Up So Far
Just got these today, the tape measure reveals that they are 6" X "4 X 2" just like the original ReliOn that came with the machine.  Quality appears similar; this one actually has a thin metal strip around the middle of the longest perimeter of the filter that the OEM did not, which might help reinforce it some compared to the original OEM.  Reinforce is relative; because I like our Hunter humidifier better, which has two permanent, hard filters that can be cleaned and reused.  I will update later if these replacement ReliOn filters don't fit the bill.