Product review (2 stars): BestAir ES12 is not a good replacement for the Emerson HDC-12
This item is supposed to be compatible with the Emerson HDC-12 filter but it is not.  It fits in the humidifier but it floats and does not absorb the water like the HDC-12, so the water is not evaporating into the air the way it is supposed to.  It stays  in the humidifier.  I ordered 2 and am not satisfied.