Product review (4 stars): Lesser quality then name brand but great value!
These filters don't have the metal inside that the name brand or manufacturer filters have.  But, truthfully we don't use my daughter's humidifier that much- except when she is sick.  In that case, I noticed the filters would brown easily and we would have to replace them each time (maybe 3 or 4 times a year).  These are only a couple dollars each so I don't mind using them for a week and then tossing them- the name brand ones were about three times the cost.