I use the herpstat by spyder robotics (www.spyderrobotics.com). They are great. Some might think they are a little pricey, but they are top quality. They have various models for multiple outputs. I think they even have one that has six outputs on one controller. You can customize each output too. They also come with the same number of temp probes as outputs (6 outputs = 6 individual thermostat probes). I personally use the herpstat 4