Product review (4 stars): This was only ok
These pads were only OK.  Maybe i expected more than what they could do.  I used these on the 450 unit, a fancy humidifier, the original make before it was redesigned.  I didn't find that it really kept the gunk off of the heating element.  And after only 2 weeks, these things would almost melt/disintegrate making clean up more difficult.