Features: The design is beautiful and exquisite, with a protective bracket and decorative small lights for excellent display effect. Humanized design, sliding the knob can adjust sensitivity, without the need for a screwdriver to turn the potentiometer, without the need for additional cable and splitters. The two sockets on the board are connected to both input and output, and can be used by plugging them in. The 6E2 electronic tube displays uniform brightness and highly sensitivity, with a built-in amplification circuit. And you can toggle the switches to select left channel, right channel, or stereo, even a single indicator board can indicate the sound of two channels. The onboard treble attenuation function highlights the rhythm of bass and drum sounds by turning on the switches, making the display more dynamic. Built in 6.3V filament drive circuit to avoid highly or low voltage, ensuring the service life of electronic tubes. Specifications: Material: ABS Size: about 8.5x6x4.6cm/3.35x2.36x1.81inch Power: USB 5V Package Includes: 1x USB Low Voltage 6E2 Electronic Tube Driver Board 1x Charging Cable 1x Left Right Channel Data Cord note: Please allow 1-2cm errors due to manual measurement. Please allow for slight color differences due to different display resolution.