Product review (5 stars): Replacement evaporator pad for Honeywell Humidifier
These filters fit our model 350 humidifier perfectly.  They are a bit more rigid than the Honeywell filters.  This is good as they don't get as misshapen as the Honeywells.  Evaporation rates seem as good, if not better than the Honeywell filters.  I haven't used them long enough to determine their lifespan, but if they last one month, I will be very pleased.