Well, there is a thermostat you can plug those Hydrofarm mats into (and I have one), but my experience is that even though the instructions say you can plug in multiple mats, it does NOT work well for more than one. Even when the mats are the same size. It did work fine for just one large mat, tho. I used it with one of my 4-flat mats and it did pretty well, although the edges do stay a bit cooler than the middle.