PRO MINI version of Mega 2560. Built on the Atmel ATmega2560 microcontroller.
Board have compact size 38x52mm. It is good solution, to make your final project on solder proto-board.
Board for functionality similar to the Arduino Mega 2560. It is embed MINI board, but the same stable, and uses the original chips ATmega2560 (16 MHz).
The board don't have USB interface. For connecting to PC, pls use the USB-TTL converter.
You can supply power to board through the power pinheaders. Output current for 5V version - about 800mA, for 3.3V version - about 800mA (Please note that the higher the input voltage the lower the outgoing current). That will provide a reliable power most of your initial projects.
On picture you can see real size of this board, compare with size of Mega Rev3.