Product review (5 stars): They have worked well for me for year and I know they will keep on working.
They work just fine on my 16 year Kenmore humidifier.  Bought a new humidifier last year, such convoluted set up that I am keeping my old humidifier until it does not work anymore.  These filters have done the trick, I have bought them for years and they work.  I change them every season (that's every winter season).  I do use reverse osmosis in the humidifier as well and a bacteriostatic treatment .  Made sure I bought a few filters, just in case.