Product review (5 stars): Great Pads that Cost Twice as Much but lasts Twice as Long
As others have mentioned, these are the Honeywell-branded OEM water pads that contain the AgIon coating. The AgIon coating is probably the major benefit for paying the additional cost for these particular pads vs the generic versions you can buy for about half the price in addition to their longevity.
I have used generic versions of this pad by "bestair" as well as "idylis" and while the pads worked ok, they ended up needing replacement after 3 months. The lack of the agion coating on the generic versions does cause a noticeable mold-like smell after about 2-4 weeks of use. I have my humidity level set to 40%, and the outdoor temperature is in the sub-30 degrees F range.
If you have a whole-house humidifier that uses this size of water pad, even if it's another brand, I recommend using the Honeywell versions. The cost works out to equal or less than the generics because the Honeywell pads last twice as long in my experience.
On a side note, make sure that you buy these directly from Amazon. I bought mine from a 3rd party seller and they shipped me generic no-name brand pads. Amazon shipped me the correct units and promptly refunded me for the faux units that the 3rd party seller sent.