Product review (5 stars): Exact OEM for my Aprilaire Humidifier Model 400
I've ordered through other retailers and this is the BEST PRICE I could find; if you have a PRIME MEMBERSHIP.
This is an exact original, matching the ORIGINAL WATER PANEL, given to me the day the evaporator was installed.
If you have a PRIME membership, it keeps track of your orders and you'll always remember to re-order the correct water panel.
I use two of these during the winter; I live in the Northeast.