Ovanligt tillbehör till Pc Engine.

Citat från Wikipedia:

" Designed for the original CD-ROM² and Super CD-ROM² peripherals, adding the 2304 kB of RAM required by Arcade CD-ROM² games. The Arcade Card Duo is for the PC-Engine Duo/R/RX consoles and adds 2048 kB RAM, because the PC-Engine Duo series of systems have 256K of RAM built-in."

Släpptes bara i Japan.