This device is just like the original Super Game Boy, except for a few new changes. The Japanese version of the SGB has a transparent blue body (as you can see in the pic above), has a few new border designs, and, this is the major addition, Game Link compatibility; the US version is identical to the Japanese version, except excpet the body is grey and not transparent. Now, you can play 2 player GB games with the SGB2. I think it can be linked to a standard Game Boy as well as another SGB2; of course, with 2 SGB2s, you would need another SNES and TV monitor. The unit also has 2 LEDs, one red, which shows the power is on to the unit, and a green one, which indicates whether or not the Game Link is being used. You can see the 2 LEDs in the pic above, and the Game Link socket is found on the right hand side of the cartridge body. This Game Link socket is different than that used on the original Game Boy, it is the same used on the Game Boy Pocket, and can be hooked up to other Game Boy devices like the Pocket Camera and Pocket Printer.
This was released in Japan, on January 30 1998, and sold for 5,800 yen. In March 1998, QVC (the home shopping channel) offered the Super Game Boy 2 for sale, for $59.95, the MSRP for the original SGB.