ARDUINO MEGA 2560 Rev3
Arduino Mega 2560 by arduino.cc is a development board based on Arduino Platform. It is powered by ATmega2560 microcontroller chip and thus has 54 digital I/O pins, 16 analog inputs, 4 UARTs and 256K flash memory. It has the same 16MHz crystal oscillator as in the Arduino Uno.
Arduino Mega 2560 is suited for the bigger projects which demand more input/outputs and more flash. In fact, most RepRap 3D Printers are powered by Arduino Mega 2560.
Arduino is an open source hardware development platform which consists of Arduino hardware(boards) and Arduino IDE, which makes it easy to program your embedded projects. Arduino has a thriving open source community where engineers from all around the world contribute with their own source code, hardware, and products.