Product review (1 stars): Thin, stiff, poor wicking performance. Avoid at all cost!
I purchased three different aftermarket brands of filters for my HAC-504 to compare them. This is easily the worst of the 4. The filter is made of very stiff, thin paper that does a very poor job of wicking up the water, which is the primary purpose of the filter! It is prone to drying out quickly and stiffening up. There's absolutely nothing positive to say about this one.