Product review (3 stars): Not the best..
These work well, but they are not the best ones I have used. The silver does prevent any mold growth, but the claims of an extended life are over exaggerated.  We've got to replace the filter about every 4 - 6 weeks, hardly the months of use they advertise. These are probably ideal for light usage, but we use our humidifier nightly, and these filters simply have not proven to be worth the extra expense.