"The WonderSwan Color is a handheld game console designed by Bandai. It was released on December 30, 2000 in Japan, and was a moderate success.
The original WonderSwan had only a black and white screen. Although the WonderSwan Color was slightly larger and heavier (7 mm and 2 g) compared to the original WonderSwan, the color version featured 64k of RAM and a larger color LCD screen. In addition, the WonderSwan Color is compatible with the original WonderSwan library of games."
Source: Wikipedia, "WonderSwan_Color", available under the CC-BY-SA License.