Product review (5 stars): OEM part
We all change our furnace filters but neglect the humidifier.  This fall I decided to check my humidifier evaporator pad. It was all corroded and falling apart.  I went to the Home supply and hardware stores and no one had the one for my model.  I found this OEM filter to be exactly what I needed, I had no idea my old one was supposed to look like this when it was new, mine was half corroded away!