The 4040 by Alpine Hardware is a replacement humidifier solenoid valve.
For Whole House Humidifiers 24 volts | 2.3 Watts | 60 Hz
The humidifier valve includes compression nut, washer and strainer.
This valve is comparable to part # 4040 Fits models 220, 224, 400, 400A, 400M, 440, 500, 500A, 500M, 550, 550A, 558, 560, 560A, 600, 600A, 600M, 700, 700A, 700M, 760 and 768.
Does not work on models 330, 445, 110, 112, 350 and 360.