The water panel is constructed using an expanded metal mesh covered with a special coating that absorbs water and removes mineral deposits.
For best performance, change at least once per season, maybe more depending on water conditions and frequency of use.
Also Fits the Following:
Aprilaire: 110 220 500 500A 500M 550 550A 558
Bryant / Carrier: HUMBASBP, 2312, 2412, HUMBBSBP, 2212, 2312, 2412
Honeywell: HE220A HE220B HE225A HE225B
Dimensions Approximately 10″ W X 9 1/2″ H X 1 5/8″ D