The GeneralAire 7520 is the correct replacement humidistat for the following humidifier models:
The GeneralAire HC-201 High Limit Humidistat is a replacement humidistat for the GeneralAire Elite Steam Humidifier models DS15, DS25, RS15, and RS25. This high limit humidistat regulates the humidity of the air and offers you more versatility in controlling the level of humidiity in your home. This is an OEM GeneralAire replacement part and is very reliable.
GeneralAire HC-201 High Limit Humidistat specifications: