The problem with those cheap ESU thermostats is that you have NO way of knowing what temperture you set them at....no digital readout of temperature. So basically, you have to adjust the dial....with the funny blue shaded to read sticker similary to the one that controls air temp on the A/C in your car.....and hope that you get the temperture right..or rely on what ever means you use to measure the temp that you set it at.

After you spend countless hours trying to get the temperature right.....then it will probably break on you.

...yep...complete waste of money.