Give the guy a break!

I have two temp gauges. One is a very expensive Raytek laser temp gauge I bought a few years ago to use in my work but also was brilliant when using for model engines. You can stand 25 feet away from a cylinder head and shoot the laser beam at it and get your temp. $300

The other is the small blue Duratrax thing you see in hobby shops and online. It must be held next to what you are temping (a couple inches anyway) and it does not have a laser beam. But it is accurate, very useful, and around $20 bucks.

If you are talking about an on-board temp gauge like the nitro car guys use, the MIP or Venom units are the common versions and the Venom is better because it has a programmable thermo shutdown feature.