I have one of those venom temp gauges with a probe that loops around the cooling head and displays the temp.

I also have a temp gun, as I heard a lot of people say how inaccurate those temp probes are. I have to say, after trial and error of what fin to wrap it around (eventually 2nd from the bottom) the temps have never been any more than 5 degrees different from my temp gun. So, at least for me, it's accurate, and it also has a peak hold function which is very usefull