This audio amplifier module is based on LM386 chip. It has a gain value up to 20. The module includes speaker terminal blocks, a power led indicator and 10K adjustable resistance, so you can adjust the volume of amplification. - Working voltage: 5 ~ 12V - Size : 41 (mm) x13 (mm) - Pin connection - GND: Ground - VCC: Voltage supply (5:12V) - IN: Audio signal - Terminal: Speaker -