Product review (1 stars): No more shopping from Allergy Be Gone
The filters I received were BestAir HW500 (1 of 4 was in the original box). They have a metal shell versus plastic on the original Honeywell HAC504. I returned them and received another set of filters which were again the same filters(HW500) I believe. They had no original box and the shell was metal, which can easily scratch its housing and stimulate mold growth in humidifier.
It is also sad that I saw another review  sent on October 2007 about similar problem(purchased as HAC504, received different) for the same item purchased from Allergy Be Gone.