Product review (5 stars): if you have an older one like mine, you might have to cross reference to ...
I ordered this for an older humidifier that was 7 years old and it fit perfectly. I searched several places for a replacement before I found the correct one. The original company that made my humidifier has been bought out by another company, but their filter fit. So, if you have an older one like mine, you might have to cross reference to get the correct one.