Product review (1 stars): Unusable within 1 week
I was hoping I just got a dud, but both filters molded within one week. We used them in the Vick's humidifier that they fit perfectly into, and I tried some of the strategies others suggested for letting the filter air out each day. But no matter what I tried it became unusable faster than the original filter. And I would have exchanged it or returned it but life with a toddler meant I did not get on Amazon to try to initiate anything till after the return window had closed. I like the humidifier itself but have not found a good filter to use with it yet.