I've recently removed this gauge from my plane. It's a Westach Model 2DA1 CHT/EGT gauge, FAA TSO-C43A, SAE-AS413B, Class III, equipped with the EGT ONLY. I broke the spark plug CHT thermocoupler awhile back when rotating/cleaning the plugs, so you'll have to purchase one of those, either the spark-plug type of the cylinder head type.
I'll offer this FREE instrument to whoever hollers first! Free shipping, handling, and packaging to the lower 48.