Feature:1. WIDE INDICATION RANGE: The tachometer provides an indication range from 0 to 4000 RPM, allowing you to observe engine performance with precision. The adjustable speed ratio from 1.0 to 360 further enhances its versatility across different engine types.2. COMPACT AND EFFICIENT DESIGN: This 52mm gauge is compact yet efficient, providing essential data without occupying excessive panel space, ensuring long lasting use.3. VERSATILE USE: Designed for use with gasoline engines, this tachometer accurately displays RPM and hours of operations, making it an essential tool for various vehicles and machinery.4. WIDE APPLICATION: The 52mm 4000RPM gauge with 7 color backlight, ideal for trucks, tractors, trailers, cars, RVs, and boats, bringing you professional and dependable use.5. EASY INSTALLATION: Simply cut a 52mm (2in) hole in your panel with a 55mm clearance behind it to accommodate the tachometer. Once the hole is prepared, insert the gauge and tighten the screws for secure mounting.Specification:Item Type: 4000RPM TachometerVoltage: DC 9-32VSize: Approx. 52mm /2inSeven Backlight Colors: Red (default), Green, Blue, White, Yellow, Cyan, Purple, AutoAuto: Switches every minute according to the above sequenceFitment: Suitable for Trucks, Tractors, Cars, RVs, Boats.Package List:1 x Tachometer1 x User Manual