Product review (3 stars): Bad humidifier (but can be modified)
I agree with the other reviewers that these or any filters for these humidifiers which all depend on wicking water upward against gravity have a short lifespan and are too costly.  Just an idea for anyone with some time, motivation, and knowhow, I was able to hook up a little fountain pump to a 1/4" perforated hose that I wrapped around the top of the filter.  This keeps the filter soaking wet and the humidifier operating at maximum output for several months without replacement.  The filters do eventually get clogged up with calcium deposits and need to be replaced but this has drastically reduced the cost of operation. A drawback is that I was not able to wire the pump to the humidifier's humidistat which means the pump must be plugged in separately and operate continuously while plugged in.  I also recommend cleaning the humidifier regularly and using the cleanest possible water to extend filter life.