Product review (4 stars): We have a Kenmore umidifier and these work great as long as you do not let your humidifier ...
We have a Kenmore umidifier and these work great as long as you do not let your humidifier run out of water (they will become stiff).  You will need to use a bacteriostatic solution because they seem to get smelly and gross within a week or so if you don't.  When properly cared for, these filters typically last us about a month and our humidifier runs almost non-stop because the air in our house is very dry during the winter months.  We have been using these filters for the past few years and will continue to do so.