Grozone Control OSW On/Off 120 Volt Switcher (Trigger Cord)Can turn on or shut off any piece of equipment by mean of a low-current 120V sense cord. On/Off switching functions (upper/lower receptacles) in one single module for increased flexibility. Example use #1: to be used with CO2 controller to stop exhaust fan while injecting CO2. Example use #2: to be used with any fan control to stop fogger or humidifier when fans are activated. Example use #3: to be used with air conditioning system to stop recirculation fans when cooling.