Product Packaging:Standard Packaging This is new SainSmart MEGA2560 R3. It now uses an ATMega16U2 instead of the ATMega8U2 chip, which allows for faster transfer rates and more memory. No drivers needed for Linux or Mac (inf file for Windows is needed and included in the Arduino IDE), and the ability to have the Uno show up as a keyboard, mouse, joystick, etc. The new MEGA2560 R3 also adds SDA and SCL pins next to the AREF. In addition, there are two new pins placed near the RESET pin. One is the IOREF that allow the shields to adapt to the voltage provided from the board. The other is a not connected and is reserved for future purposes. The MEGA2560 R3 works with all existing shields but can adapt to new shields which use these additional pins. New Features : 1.0 pinout: added SDA and SCL pins that are near to the AREF pin and two other new pins placed near to the RESET pin, the IOREF that allow the shields to adapt to the voltage provided from the board. In future, shields will be compatible both with the board that use the AVR, which operate with 5V and with the Arduino Due that operate with 3.3V. The second one is a not connected pin, that is reserved for future purposes. Stronger RESET circuit. Atmega 16U2 replace the 8U2. Specifications : Microcontroller: ATmega2560. Operating Voltage: 5V. Input Voltage (recommended): 7-12V. Input Voltage (limits): 6-20V. Digital I/O Pins: 54 (of which 15 provide PWM output). Analog Input Pins: 16.00. DC Current per I/O Pin: 40 mA. DC Current for 3.3V Pin: 50 mA. Flash Memory: 256 KB of which 8 KB used by boot loader. SRAM: 8 KB. EEPROM: 4 KB. Clock Speed: 16 MHz. Package Content : 1 x Mega2560 R3. 1 x USB Cable.