HiLetgo 3pcs PRO Mini Atmega328P-AU 5V/16MHz Development Board Microcontroller Bootloadered Pinout is identical to Arduino Pro Mini Compatible to Arduino IDE with Pin Headers Chipset: Brand new Atmel Atmega328P-AU. Pinout is identical to Arduino Pro Mini. Bootloadered already in the board, easy to get started. Support power supply by external 3.3V~12V DC power and 9V battery power. Support serial downloading, 100% Compatible to Arduino all series shields and sensors.