Simply slot the TypePak into a keyboard with a compatible Game Boy cartridge slot, flip the power switch, and you've got yourself a working wireless keyboard. Rather than leave twenty precent of the TypePak's cartridge pins unused, several of the important pins are exposed on both ends of the cartridge's edge connector. The TypePak needs a custom PCB, a cartridge shell, a cartridge slot, a display connector, a shift register, and several surface mount capacitors.