Product review (2 stars): Poor quality control
I have purchased these twice.  The first time the filters were just fine. The second batch is horrible.  Out of the 4 filters in this box, no two are the same size.  Two of the filters are almost 3/4 inch too small for the humidifier and two of them were 3/4  inch and 1 inch too large for the humidifier. To get them to work, I had to trim some off of two of the filters and remove some of the glue from the other two to stretch them to fit. The mismatched size was clear from the moment I opened the box, the smaller ones were clearly smaller than the others.

The Next time I purchase filters for my humidifier, I will not use this brand.