The Aprilaire Scale Control Insert 4403 is the U-shaped component which encases the Water Panel. It directs any built-up mineral deposits back into the water panel, and it prevents water from leaving the wet-pack section and entering another portion of the humidifier. Used with the water panel number 45, and the distribution tray number 4407
Note: Float assembly (SKU: 4406) and the Float Cover (Sku: 4405) are not included