Features: brand new and high quality The package includes high-precision VU ammeter and driver board. AC/for DC 12-16V power supply. This is the dual channel input terminal for driving the low level signal of the electric board, which can connect the audio of the mobile phone, computer sound card and the front level audio source equipment (the signal is the signal that can be heard by the headset). When wiring, L,G and R respectively correspond to the left and right channels of the audio source equipment. The adjustable power "5K-V" is used to adjust the backlight of the VU meter. Model input: ≤0.775V. Specifications: Material: ABS Size: 60x50mm/ 2.36x1.96 in Package Includes: 2x VU ammeter 1x Driver Board 1x Cable note: Please allow 1-3cm error due to manual measurement. pls make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item.