Product review (5 stars): Closely match OEM filters; Well made
We have an old Sears Kenmore humidifier that keeps chugging along.  We've ordered 3rd party filters before that were either poorly made, or didn't fit properly, or both.  These ones match the size and style of the OEM versions, and work great.

BTW, I have taped a doubled piece of window screening on the back of the humidifier at the air inlet.  This does SLIGHTLY restrict the flow of air, as evidenced by the slight change in tone, and slight increase in sound of the fan when the screening is in place, but the humidifier still works fine (as evidenced by roughly comparable amount of water usage.  The benefit is that the screening can be easily removed, rinsed under running water, dried, and replaced.  Some house dust still gets through, but the screening stops a lot of it.  Consequently, we can get a full season of usage out of each air filter wick...  perhaps flipping it over once, mid-winter.  Eventually, mineral deposits become too great.