It's blue! It's skinny! It's the Arduino Pro! SparkFun's minimal design approach to Arduino. This is a 3.3V Arduino running the 8MHz bootloader. Because the system voltage for this board is lower than other Arduino development boards, it may not be compatible with many Arduino shields which were designed to run at 5V. The Arduino Pro 3.3V still works great with our prototyping shield so you can create your own 3.3V shields. The lower system voltage also has its advantages, like ease of use with many common 3.3V sensors. Arduino Pro does not come with connectors populated so that you can solder in any connector or wire with any orientation you need. We recommend first time Arduino users start with the Uno R3. It's a great board that will get you up and running quickly. The Arduino Pro series is meant for users that understand the limitations of system voltage (3.3V), lack of connectors, and USB off board. To keep things affordable and low profile, we've chosen to make the DC power jack footprint available, but not to populate it. We recommend running the board with a LiPo battery for better portability. Also, to keep the cost low, we made changes like using all SMD components and switching to a two layer PCB. Project description, more information and ordering can be found at https://www.sparkfun.com/products/10914 Arduino Pro Homepage: http://www.arduino.cc/en/Main/ArduinoBoardPro Getting Started: http://www.arduino.cc/en/Guide/ArduinoPro