The refrigerator thermostat easily installs onto your existing refrigerator or freezer for precise temperature control. No tools are required; to install, simply plug the controller into your wall outlet (up to 12 amp 110 volt), plug your refrigerator or freezer into the controller, and run the temperature probe inside the refrigerator or freezer. Essential for true lagering, or to gain more control over keg or hop storage. Adjusts between 20- 80 oF and features a 3 1/2o differential, which saves wear and tear on the refrigerator compressor by reducing the frequency that the unit cycles on and off. Manufactured by Johnson Controls.