An RPM gauge, also known as a tachometer, measures the rotational speed of an engine's crankshaft in revolutions per minute (RPM). It provides drivers with important information about engine performance, helping them understand when to shift gears for optimal efficiency and power. Typically found on the dashboard of vehicles, the RPM gauge features a dial with a needle that indicates the current RPM level. Monitoring this gauge can prevent engine damage by alerting drivers when they are operating at excessively high speeds, ensuring a smoother and safer driving experience.