Visual Memory Unit (VMU)
The VMU is a device specifically used for the Dreamcast to store saved games, display data, and play simple games. In the case of 4×4 Evolution it can be used to store one additional race track to act as downloadable content. It provides a usable capacity of 100KB of flash memory. As the heightmap alone is 128KB this required several unique tricks in order to allow for custom content to fit within this space. See LTE Tracks for more information.