This product works exactly as expected and advertised. Choose either heating or cooling, set lower and upper temperature bounds, and place the temperature sensor wherever you need it. The controller will turn on power to the outlet when the temperature reaches one bound, and will turn it off when it reaches the other. As long as the device you plug in is configured to turn on automatically once it receives power, it should power cycle as the temperature fluctuates.

The reason it only gets 4 stars is because this simple on/off mechanism is not a very good design for a temperature controller. For a system where the temperature changes relatively slowly, like a sous-vide, it should work fine because the temperature won't change much after the power is turned off. For a system where the temperature changes quickly, like a toaster oven, it won't work very well - the heating elements are still hot when the controller shuts the system off, so the temperature will overshoot. Similarly, when the temperature comes back down and the controller turns the oven back on, it takes time for the elements to heat up so the temperature will undershoot. The proper way to do this is with a PID controller, which keeps track of the temperature history and how fast temperature is changing, in addition to the current temperature. Such a controller can maintain the temperature precisely regardless of how quickly the system being controlled works. Also, it's not much more work to implement than a simple on/off controller.

From a practical standpoint, for those of you facing this problem, an alternate solution is to put a large thermal mass (e.g. a big hunk of steel) into the toaster oven, and attach the temperature sensor directly to that mass. This will slow down the rate at which temperature changes, so the controller should work properly (although it'll take longer to get up to temperature, and to come back down after).

working well for sous vide in conjunction with a crockpot (the controller plugs into the wall, the crock plugs into the controller).

its not perfect....a bit hard to follow the instructions, but the examples in the instructions help a lot. For the price though - being able to turn a crockpot I already have into a sous vide cooker has saved me a couple hundred bucks (which I used to buy more steak).

a couple more iterations of this product with more intuitive controls and I bet single use sous vide cookers become a thing of the past.

I am using mine to do sous vide in a 4qt crockpot. no actual cooking yet, but my tests are surprising. Put the crock on low setting and this thing can keep the water temp within 1 degree F. After some tests I came to realize that the controller is not the issue in terms of keeping the water within .1 Degree F. It is the crock pot which must cycle on and off to hold the temp. I decided upon 127.5F and 128 as the range. Works just as well as a $200 ANOVA. Of course, the crockpot is only 200 watts. The ANOVA is 800 watts and can circulate the water. But, given the savings I'll have fun not being perfect. Pretty cool little device.

I have some electronic equipment on the top shelf of an unventilated closet. During some of the warmer days this summer, I was experiencing some equipment problems and found it was much warmer there than I'd expected. I bought a small fan to circulate the air, which helped a lot, but I didn't want to leave it running 24/7/365, especially since it won't really be needed most days. This unit fills my need PERFECTLY. There's a nice long wire on the sensor so I can put it right up by the equipment while keeping the control unit on a lower shelf where it's readily accessible to me. Setup could be a little easier, but it's not terribly complicated, either. I just received it earlier today and so I haven't used it long, but barring any ugly surprises I expect this will do exactly what I need it to and keep my electronics from frying.

This has been my first purchase of such a device.Actually, I was first looking for a wine cooler or a small box that would keep my veganized kefir cultures at around 67 degrees; it's the right temperature to have a slow fermentation and get a rich, thick kefir from soy milk. However, finding an inexpensive cooler turned out to be more complicated than expected. Most of them do not have a good thermostat, are too expensive and too large. So, I decided to look for a temperature controller as I have an old, unused mini fridge. I ended up ordering this digital temperature controller because it seems to have everything included (there is a cheaper unit from another brand but you have to buy the sensor separately) and has the right features I needed: cooling/heating mode, accuracy: ±0.5 and keeps the setting even after a power failure.

The temperature controller came in a white, easy to open box. The temperature controller looks better than expected and the LCD screen is very easy to read.

The advantage of this unit is its simplicity, even though it has many features, The manual is easy to follow (not perfect English but written well enough to fully understand the instructions). The only thing one could mess up here is connecting the power cords wrong if one doesn't pay atttention where input and output is. What I want to note here is that I may have received slightly different unit as pictured in the product page as the output socket looks quite different and looks like I can plug in several types of plugs, not only standard US ones.

It took me less than 2 minutes to connect all cables and set the temperature controller to cooling mode. Before trusting my kefir grains, I did a quick check on the unit. I opened the fridge door to warm up the temperature and to see if the temperature controller turns on the fridge at the set maximum temperature; it did. Then, I waited to see if the temperature controller turns off the fridge once the temperature reading reached 67.5 degrees and it did. The temperature fell 2 degrees beyond but that is due to the cooling coils and not the temperature controller's fault.

In my pictures you see a bluetooth wireless thermometer which measures the temperature of the kefir liquid, not the air temperature of the fridge itself. I did test the accuracy of the temperature controller with a digital fridge thermomether and the reading, compared with the temperature controller, was off only by 0.4 degrees. So, my unit is working just fine.

So far, this temperature controller worked flawlessy and my veganized kefir grains seem to love the constant temperature as they multiply now at a higher rate. Maybe I need to start selling my kefir grain overpopulation LOL.

In the end, I'm very happy with this user-friendly temperature controller. Very easy to install and to input the right settings.