These cards are designed for the BIGAVR6 Development System, in case you want to change or have a spare CPU for your BIGAVR6 system (or to design your own system using the same DIMM CPU module format).
You can purchase one of these cards only with an ATmega128 microcontroller in TQFP mounted along with an oscillator. (The other CPU options that used to exist are no longer available.) The picture to the right shows two cards for illustration purposes. The purchase price is for one card only. Download BIGAVR6 MCU Cards Manual