OEM AprilAire Water Panel Evaporator Filter Humidifier Stock No. 10 (Pack of 2)
This Aprilaire Humidifier pad fits Humidifier models 110,220,500,500A,500M,550,550A and 558. AprilAire 10. For 110, 220, 500, 500A, 500M, 550, 550A, and 558 Whole-House Humidifiers.