PRO MINI version of Mega 2560. Built on the At mel ATmega2560 microcontroller.
The board have compact size 38x52mm. It is a good solution, to make your final project on solder proto-board.
Board for functionality similar to the Mega 2560. It is an embedded MINI board, but the same stable, and uses the original chips ATmega2560 (16 MHz).
The board doesn't have USB interface. For connecting to PC, pls use the USB-TTL converter.
You can supply power to board through the power pin headers. Output current 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 the picture, you can see the real size of this board, compare with the size of Mega Rev3.