Product review (5 stars): I am so glad to find these
I am so glad to find these.  I used them last winter and already need them this year. You have to buy the trays to put them in separately.  I have to fill them morning and night; but they put out a lot of water without having to use electricity to run a humidifier.  Every time your furnace kicks in to warm you and dry out your skin the air flows into your room over wet wicks.  I used to buy machines the blew air over wet wicks.  They held more water but were always breaking down or getting mold in them.  These trays don't mold easily and if you think they need it can be placed in the dishwasher to sterilize.  I did that last spring and they were ready for now.