AutoHack combines a passion for all things automotive and the latest technology. Our vision is to bring you new and improved methods of solving automotive issues and enhancing your ride. All of our tachometers offer wireless transmission to simplify your installation and measure RPM directly from your engine. Our Standard Black Gauge is an in-dash option that has an RPM range of 0 – 4,000. This diesel tachometer is 85mm (3 3/8″).