Arduino Leonardo R3 Board
Arduino Leonardo is another popular development board from Arduino, based on the ATmega32u4 Microcontroller. The board is similar to UNO and supports 20 Digital I/O pins with 7 PWM pins, a 12 channel 10-bit ADC and supports upto 16MHz clock frequency.
The specialty of Leonardo is that unlike UNO it has a built-in USB communication without the requirement of additional hardware, this enable the board to be used as HID devices like wireless mouse or keyboards. Along with Serial port (COM) communication it also supports Virtual CDC communication.