ITEM NAME:DC 5V-12V LM386 electret microphone power amplifier board gain 200times mi*SE 100% Brand New and High Quality LM386 amplifier chip, the magnification can be adjusted by the board above the adjustable resistance between 20 times to 200 times, you can directly drive low-power speakers for the use of electret microphone. Operating voltage: DC 4V-12V Board size: 20mm * 20mm Package Included: 1 x LM386 Headphone Amplifier Board.1 x LM386 Headphone Amplifier Board. Board size: 20mm 20mm.