he Pura 44302301 Control Module (Ballast) can be used with Pura UV20 & UVB 120 volt ultraviolet water disinfection systems that are equipped with a "Normally Closed" (NC) solenoid valve control, but not equipped with an audible alarm. Voltage: 120 Systems: UV20, UVB Lamp Out Circuit with Alarm: N/A Lamp Out Circuit with Solenoid Valve Control: Normally Closed (NC) UL Listed 41Y4