well you stick the thermostat probe on the middlemost shelf right on the flexwatt.
Ranco and johnson control stats from reptilebasics.com are on the cheaper end and are pretty good. I have a johnson control on my rack and it is doing well.
The helix and herpstats are a little more expensive but much nicer in the long run.
Ok but then does the thermostat control the temperature of the flexxwatt? Any other major things id need to know?