Believe it or not, this board is a small development system. It barely fits on your finger, but the MINI-AT Board 3.3V features ATmega328, USB-UART, reset circuit and LED indicators. It's compatible with standard DIP26 sockets. The onboard voltage regulator allows the board to be powered directly from the USB cable. It features a 16MHz SMD crystal oscillator.
Both come preprogrammed with a fast UART bootloader with 57600 bps operation, so no external programmers are needed for development.