This refers to the Game Boy Pocket portable console. Since the console was not region locked, this entry refers to all regions the console was sold in.

From Wikipedia:

In 1996 Nintendo released the Game Boy Pocket: a smaller, lighter unit that requires fewer batteries. It has space for two AAA batteries, which provide about 10 hours of game play. The Pocket has a smaller link port, which requires an adapter to link with the older Game Boy. The port design is used on all subsequent Game Boy models, excluding the Game Boy Micro. The screen was changed to a true black-and-white display, rather than the "pea soup" monochromatic display of the original Game Boy. Also Game Boy Pocket (GBP) has a larger screen than the Game Boy Color (GBC) that later superseded it, the GBP's screen is 65mm (2.56") diagonal, width 48.5mm (1.91"), height 43.5mm (1.71") compared to a 59mm (2.32") diagonal for the GBC. Again, and like the Game Boy, the Game Boy Pocket has no backlight to allow play in a darkened area. The first version did not have an LED to show battery levels. This was soon added due to public demand, along with new Game Boy Pocket units of different colors, some of them new to the Game Boy line. There were several limited-edition Game Boy Pockets including a metallic Ice Blue unit and a pink model exclusive to Japan. The Game Boy Pocket was not a new software platform and played the same software as the original Game Boy model.