Now you can keep your beer or wine within one degree of the set point on your digital controller. Designed to fit either 3, 5 or 6 gallon PLASTIC carboys or any other similarly sized opening hole. The unit comes with a 15″ stainless steel thermowell and a #10 silicone stopper. It can be used in any container with a stopper opening of this size where you need to accurately monitor and control liquid temperature.