The speedometer is operation ready with all known electronic speedometer sender signals. The electronic 7000 RPM tach works with virtually any engine output signals. The Ultimate Speedometer is 3-3/8-inch in diameter. It includes an odometer and comes with its own plug-in harness. These gauges are American made and available in six standard face designs. All instruments carry a full five year warranty. Contac Classic Instruments at (800) 575-0461 www.classicinstruments.com