Its not a bad gauge - seems accurate - I put one in my 1st Tmaxx - it has a wire loop that has the temp sensor (thermistor) located in the loop. You locate the cooling fin thats closest to the shoulder of the glow plug height wise and push the sensor all the way in next to the inside where the fins join the head. This was where mine gave the closest readings to my Raytech temp gun.

Only downside - mine was tough on batts. Seems like the batt was always dead when I went to use it, so keep a spare on hand.

If you're going to have another nitro RC, get a gun that will work on both, this onboard one is not intended for moving.