1, by the pickup, amplifier, MCU and LED components 2, pick up the music played through the pickup, analyze its spectrum, and display it through the LED 3, the pickup sensitivity is adjustable 4, can set the display refresh speed, audio response sensitivity, sampling frequency and other parameters Kit name: Voice-activated in-line LED Music spectrum Kit Power supply :USB power supply 5V Operating voltage :5V Note: There are differences in components between different batches, which does not affect the use Colour: Black+Transparent Material: PCB+components+acrylic Package Contents: 1 x PCB Soldering Project Practice(It's diy kits. Need to solder by yourself)) Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.