A ECU Master is a computer that managest the spark ignition of engines. There is a Black version that is suitable for race cars but also other applications like bikes and boats. The most important thing about these computers is the impact it can have on fuel consumption and power of the engine. All ECU:s are programmable so that you can tailor the ECU to your car and your specific circumstances. It is recommended that if you have a race car of any sort you should invest in a better ECU for maximum performance. A lot of people wonder if it is also recommended to install a new ECU to ypur ordinary car. This is probably not worth the cost. The effect you can get out of a normal car is not very big so be cautious before investing.