This is the awesome Venom Racing Micro Temp Gauge. This temp gauge measures temperature in Celcius or Fahrenheit. It is very small, and it is actually 40% smaller than the original. It will fit nearly anywhere, and at this great price, it is a steal. Why risk destroying your several hundred dollar car, truck, or boat engine when you don't have to even worry about it? This helps greatly when tuning your engine. The battery is included.