Product review (4 stars): They work.
These fit our Holmes humidifier just fine, and seem to have as good life or better than other filters I've used.
Bought these primarily because of the relatively low price (at the time), and have been impressed by their quality.  The surrounding mesh seems to be a plastic rather than a flimsy aluminum mesh, so should hold up better when I rejuvenate them with a vinegar soak.  The filters with the aluminum mesh tend to fall apart.