Arduino Pro Mini ATMEGA328P is a 3.3V Arduino (Official Version) running the 8MHz boot-loader. Arduino Pro Mini ATMEGA328P come with connectors so that you can solder connector or wire with any orientation you need. We recommend the first time Arduino users start with the Uno R3. It’s a great board that will get you up and be 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.