Product review (4 stars): No problems: holds up well and fits the Graco Cool Mist
I've been running my humidifier almost daily/nightly (Chicago winters are terrible) for the past month with this filter. While it has yellowed some (I figure that can be expected), there is no mold or anything of that sort. It fits well and holds up just as well as the Graco name brand ones did. I do wish these were less expensive though, because after buying a few you've spent the same amount on filters as the humidifier had cost.