This is a Visual Memory Unit (VMU) that fits in your Sega Dreamcast console. The Sega Dreamcast was a popular game console in the early 2000s. The VMU is a tiny memory card that stores your saved games, game records, and other data. It allows you to transfer data between different Dreamcast consoles. This unit is compatible with all Dreamcast games and is made in Japan. The brand of this memory card is SEGA and the unit type is an external attachment.