The
TSS2 is what you want. It is a few more bucks than the single stage, but you'll thank me later.
You use one stage for the cool side, then, depending on where you live, you can hook the other up to power a small ceramic "lizard lamp" for warming. This is great for those Feb/Mar/Nov/Dec brews here in the lower midwest, where it is 75 one day, 40 the next.