This is a VERY capable controller with lots of customizable options. HIgh quality. Clearly this was made by some very smart physicists and mathematicians. With this comes a rather steep learning curve in programming it and setting it up. Once you spend the requisite time the effort is well worth it. It only works in degrees centigrade. There is some discrepancy regarding the wiring diagrams. The solid state relay is much better than the old mechanical relays.