1. When powered on, the digital meter will read the voltage for 1 minute and switch to the air-fuel ratio.2. Switch back to voltage only when decreasing or increasing.3. This digital meter is black with bright blue LCD readout.4. Easy to install and durable.5. High sensitivity and easy operation.6. Illumination on the dial for easy reading in the dark.7. Fits most 12-volt gasoline vehicles.8. Parameters:Size: 2 inches or 52 mmPower: DC12V, IGN MAX 0.3AInput voltage: 0-1.0VDisplay range: 20.0%~10.0%Voltage reading: 8~16VNumerically accurate: every 0.5%20 LEDs: Red x 4, Yellow x 10, Green x 6