Product review (4 stars): OK with a flimsy seal.
Once you buy the humidifier this fits, you pretty much have to buy this so reviews probably don't make much difference other than, possibly, a way to let the manufacturer know the flaws and that their customers know the flaws.  The filter is ok and works but the seam where it is formed into the circle is really poorly done.  Handle this filter with extreme gentleness and care or that seam will tear.  Even a small tear renders the filter useless because the air will take the path of least resistance.