Nintendo released the Super Game Boy 2 in 1998 in Japan. Although there are unsubstantiated rumors that it was released in the United States through mail-order, Nintendo states otherwise. Additions included a link port to allow a user to access two-player mode via the link cable, a green game link LED and a red power LED indicator. In addition, it came with eight new default borders, which replaced those in the original model (except for the plain black border, present in both models), however, it retained the same built-in palettes and coloring tools as on the original model. Contrary to rumours, the system is unable to run Game Boy Color-exclusive games. One of the flaws is the system's inability to change borders in some games which have built in borders. Some games have features only available through the Super Game Boy 2, such as a special Tetris DX border.
Source: Wikipedia, "Super Game Boy", available under the CC-BY-SA License.