arduino leonardo with headers [a000057] arduino.org the arduino leonardo is a microcontroller board based on the atmega32u4 (datasheet). it has 20 digital input/output pins (of which 7 can be used as pwm outputs and 12 as analog inputs), a 16 mhz crystal oscillator, a micro usb connection, a power jack, an icsp header, and a reset button. it contains everything needed to support the microcontroller; simply connect it to a computer with a usb cable or power it with a ac-to-dc adapter or battery to get started. the leonardo differs from all preceding boards in that the atmega32u4 has built-in usb communication, eliminating the need for a secondary processor. this allows the leonardo to appear to a connected computer as a mouse and keyboard, in addition to a virtual (cdc) serial / com port. it also has other implications for the behavior of the board; these are detailed on the getting started page (http://arduino.cc/en/guide/arduinoleonardo). product page: http://arduino.cc/en/main/arduinoboardleonardo. this version has the headers pre-soldered