Ink-Bird ITC-308 temperature controller represents a great value for a 2 stage temperature controller. Plug in a heating and cooling device (or just one device if that's all you need), set your target temperature, then set the differential so that the two devices don't fight each other trying to simultaneously cool and heat. What differentiates this model from other Inkbirds out there is the differential settings - ITC-306 only has a low differential for the heating side. ITC-310 is focused on multiple timed settings rather than overall temperature monitoring. This is the right one for homebrewers!