Weight: 25 g Length: 68.6 mm Width: 53.4 mm Analog Input Pins: 6 Clock Speed: 16 MHz Operating Voltage: 5VS RAM: 2 KB (ATmega328) EEPROM: 1 KB (ATmega328) Stronger RESET circuit Atmega 16U2 replace the 8U Microcontroller: ATmega328 Input Voltage (limits): 6-20V DC Current per I/O Pin: 40 mA DC Current for 3.3V Pin: 50 mA Input Voltage (recommended): 7-12V Digital I/O Pins: 14 (of which 6 provide PWM output) Flash Memory: 32 KB (ATmega328) of which 0.5 KB used by bootloader 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 with both the board that uses the AVR, which operates with 5V and with the Arduino Due that operates with 3.3V. The second one is a not connected pin, that is reserved for future purposes