HALJIA MAX9814 High-performance Electret MIC Microphone Amplifier Modu
Amazon.com: MAX9814 Electret Microphone Amplifier Board Module MIC Auto Gain Max 40dB/50dB/60dB Frequency 2.7V-5.5V with Pins for Arduino : Electronics
Wiring and Test | Adafruit AGC Electret Microphone Amplifier - MAX9814 | Adafruit Learning System