Feature: 1. Read the air‑fuel mixture from 10 to 20 AFR, rich: 18‑20 AFR, optimal: 12‑18 AFR, lean: 10‑12 AFR. 2. Monitoring the air‑fuel ratio of the car, allows you to change the air‑fuel ratio to maximize power and engine performance, reduce emissions, and improve fuel economy. 3. Hhighly visible, it can be easily viewed from all angles under any lighting conditions. 4. Easy to install, including wiring harness and necessary installation hardware, no other sensors are required. 5. 2in in diameter, black dial, luminous red needle and black face gauge. Strong compatibility, universally used in cars, SUVs, vehicles, automobiles, etc. Specification: Item Type: Air Fuel Ratio Gauge Material: ABS Color: Black Diameter: Approx. 52mm/2in Readout: Blue digital LED Power: 12V/Maximum 0.3A Visual Angle: ≤180° With red, green, yellow LED Accurate electronic reading, 20 LED showing Fitment: Universal fit for most of cars How to Use: 1. Connect the power cord to the meter. 2. Black represents the negative pole, it can be used when connected to the negative pole of the vehicle. . Package List: 1 x Air Fuel Ratio Gauge1 x Wire Harness1 x Manual Note: Professional installation is highly recommended.