Product review (5 stars): Great product, but follow the instructions carefully.
I've been using these filters for two years and have been pleased both with the quality and timely delivery. I would recommend that prospective buyers double check the serial number of their humidifier unit. The filters come in different sizes and the unit will not function properly with the wrong size. I also strongly recommend the use of the bacteriostatic, algae and mildew liquid to avoid unhealthy growth in the water chamber and on the filter.