Product review (3 stars): Better than no filter; not an exact fit for my son's train humidifier as water tank wobbles a bit.
Got this for my son's train humidifier.
It works better than no filter.
One thing to note is that post in the center of filter maybe too high.
The water tank is able to sit on top of the cartridge, but a millimeter or two of wobble of the water tank is noticeable.