Adafruit-ATmega 32u 4-Breakout-Board-Adafruit-296-P-The-Adafruit-ATmega 32u 4-Breakout-Board-is-a-neat-breadboard-friendly-32U4-ready-to-plug-in-to-a-USB (Universal Serial Bus)-port-for-power-&-programming-Running-at-16 M Hz-the-32U4-has-32kbytes-of-Flash-2-5kbytes-of-RAM-&-1kbytes-of-EEPROM-Plus-of-course-it-has-a-full-speed-USB (Universal Serial Bus)-2-0-interface-&-a-bootloader-The-bootloader-is-open-source-&-works-with-AVRdude-P-P-Other-features-include-a-big-user-friendly-Reset-button-a-500m A-fuse-on-the-USB (Universal Serial Bus)-power-a-pow