3 power outlets? To my knowledge they only made 1,2 and 4. The older herpstat pro has 4 independently controlled proportional outlets. They are great units, I have 4 of that model. The new HS4 has better safety features so before you buy you should at least know how much that the current models are. I would if the used price was around the 25% less than new price forget the used one and buy new. For me a small savings like this a new one has better features and less wear and tear.