Correct timing is a critical part of the ignition process of a engine; if incorrect it won't only make the engine run inefficiently, but it can also be damaging to internal components. For those who have been making repairs or maintenance to their vehicle that has required movement or removal of the distributor, a timing light like the ToolPRO Professional Angled Timing Light is an important tool in order to align the ignition timing perfectly. This ToolPRO Professional Angled Timing Light is used for most 12-volt negative-ground vehicles with gasoline engines, especially 4-stroke engines. The ToolPRO Professional Timing Light may also be used on vehicles equipped with DIS (distributor less ignition system). Product features: - Voltage meter: 10 to 16 volts DC (+/-1% accuracy) - Advance angle meter: (2 & 4 cycle DIS & Conventional): 0o to 90o (+/- 0.5% accuracy) - Tachometer: 249 to 9,990RPM (+/- 1% accuracy) - Dwell angle metre: 0o to 1800 / 2-12 cylinders (+/- 1% accuracy)