Features: VU Meter: Stable and reliable performance. Easy to use. Driver Board: Fourth generation driver board design improves performance and precision. Compatible with Toshiba 7318 IC, enhancing drive capability to address limitations such as small pointer swing and low sensitivity. Compact size, easy to install. Well constructed and durable. Instructions: 1. Use AC or DC 12-15V power supply for transmission plate. Independent power transformer is recommended, or use separate winding power supply. Backlight consumes 45mA current when active. 2. L, GND, R: Low-level signal input terminals. Connect to audio sources such as CD players, computer sound cards, preamplifiers, or other signal devices. L connects to left channel, R to right channel, GND to ground. 3. R1 and R2 are adjustable resistors on the driver board that control the amplitude of the pointer movement. 4. The backlight requires DC 12V power. A voltage regulator must be used after the driver board for proper operation. 5. Ensure correct polarity when connecting power and signal interfaces. To extend backlight bulb life: 1. Reduce operating voltage to meet brightness requirements, which can significantly extend bulb lifespan. 2. When using AC power 10-12V, add a 50 ohm series limiting resistor to reduce inrush current during startup. Specifications: Material: Plastic + Metal Color: Black Backlight Voltage: AC/DC 6-12V Measuring Range: 0-500μA ±10% Resistance: 650Ω ±10% Accuracy: ±5% Calibration Point: Full-scale 500μA VU Meter Size: Approx. 35 x 35 x 37mm / 1.38 x 1.38 x 1.46 inches Quantity: 1 Set Note: Please allow 1-3mm error due to manual measurement. Ensure you are comfortable with this tolerance before purchasing. Due to differences in monitor displays, the actual color may vary from the image shown. No retail packaging included. Package Contents: 2 x VU Meter Panel 1 x Driver Board 5 x Cable