Aprilarie 10 (4-Pack) - Replacement Water Panel Humidifier Filter For Aprilaire Whole-House Humidifier Models 110, 220, 500, 500A, 500M, 550, 550A, 558

Aprilaire 10 Water Panel for Humidifier Models: 110, 220, 500, 550, 558 Genuine Aprilaire Water Panel Replacement Made in Wisconsin, USA Fits Aprilaire Humidifier Models: 110, 220, 500, 550, 558 Water panel dimensions are 10" H x 9.75"L x 1.75"W Optimizes humidity levels in your home.