This is the #1 humidifier solenoid replacement on the market. Directly replaces the Aprilaire 4040, and 100's of other units with a fitting changeout.
This universal humidifier solenoid replaces 99% of all humidifier solenoids out in the field including:
Aprilaire #4040
General #990-53
Honeywell #32001639-002
Skuttle #A01-0814-148
Carrier #4357