Features: Used to measure the RPM of automobile engine. Measurement range is 0~8000RPM. High accuracy and easy operation. Works on 1 2 3 4 5 6 7 8 cylinder gasoline vehicles or 1 - 2 cylinder new motorcycles. Adjustable shift light on face. Note: 1. It's normal the pointer is not zero in the absence of installation. After power-on, the product will check and adjust the pointer by itself. 2. If the product pointer is still not zero after power-on, can start normally, when the pointer is above zero, it can be restarted to adjust the pointer after power-off. Specifications: Color: Black Material: ABS Background light: blue light Input Voltage: 12V Package Size: 14 * 14 * 14cm 5.5 * 5.5 * 5.5in Weight: 367.5g 13oz Package List: 1 * 3.75" Tachometer Gauge 1 * Installation Instruction 1 * Package of fitting Note: NOT suitable for diesel vehicles, Only for 12V petrol vehicles.