Product review (5 stars): Buy confidently, as the hard work has been done.
I use these filters in my HW 6011 whole house humidifier.

I never got my hands on an *original version* OEM HW brand filter, which included a layer to clean the air, and by all accounts was far superior to their current offering. The reason a company begins selling an inferior product is usually $money$, but I needed details, and wanting the best performance and function out of my humidifier, I set out on the hunt, for many months, trying to find answers and hoping to find the best filter available at an appropriate price.  Along my travels, I got my hands on some real DUDS, and I also discovered that apparently HW changed their design so that the single size filter would fit more model$ (at the expense of those who purchased 6009-6011 humidifiers.) Well, Im happy to say my hunt ended here.

Theses filters are thick, stout, absorbant, reinforced, and resistant to the nasties. They are superior in all ways to the current OEM filters, and they are better priced as well. They include the air cleaning layer that I have to guess is similar to the original OEM design. I cant yet tell you how long they last, but Im guessing theyll last at least twice as long as the OEM I received with the himidifier, which with careful handling lasted me almost 4 weeks running constantly.

I wish this review had been here for me when I set out on my research as it would have saved me a lot of time. Buy confidently, as the hard work has been done.