Aprilaire 4040 Solenoid Valve, 24 Volt for Aprilaire Whole House Humidifier Models 400, 400M, 500, 500M, 600, 600M, 558, 550A, 550, 568, 560A, 560, 700, 700M, 768, 760A, 760, 0.5 Ounces. Compatible with AprilAire Whole House Humidifier Model: 400, 400M, 500, 500M, 600, 600M, 558, 550A, 550, 568, 560A, 560, 700, 700M, 768, 760A, 760.
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