Aprilaire 24-Volt Transformer | 24-Volt Plug-in Transformer

The leads connect to your 110 volt supply, and the screw terminals then provide the 24 volt output to the humidifier. The Aprilaire 4010 Humidifier Transformer Is Designed For Use With Aprilaire Humidifiers 400, 550, 550A, 558, 560, 560A, 568 Amp; 600 Aprilaire 24V Humidifier Transformer. Mounts In A Utility Box From The Brand Name: Aprilaire