Pro Micro Atmega32u4 is compatible with Arduino IDE, very small and powerful microcontroller development board. The integrated USB transceiver makes an additional USB-TTL bridge IC obsolete. Together with the micro USB port, Pro Micro Atmega32u4 is only 4 mm high. With dimensions of 34 x 18 mm is Pro Micro Atmega32u4 only 3/4 of the size of an Arduino Nano, and only half of its height.The tiny little Pro Micro Atmega32u4 board does all of the Arduino tricks that you’re familiar with:9 channels of 10-bit ADC, 5 PWM pins, 12 digital I/O as well as hardware serial connections Rx and Tx. Running at 16MHz and 5V, this board will remind you a lot of your other favourite Arduino-compatible boards but this little guy can go just about anywhere.There is a voltage regulator on board which can accept a power supply of 6-9VDC (max. 10V). Make sure to connect the input voltage to the RAW pin and not VCC (5V).The Pro Micro board is originally developed as open hardware by the company Sparkfun. It comes with the Atmel Atmega32u4 MCU and runs with 16MHz. A pair of pin headers are included, as shown in the picture.Features:ATmega32U4 running at 5V/16MHzSupported under Arduino IDE v1.0.1 and aboveOn-Board micro-USB connector for programming9 x 10-bit ADC pins12 x Digital I/Os (5 are PWM capable)Rx and Tx Hardware Serial Connections