What is this thing sitting in slot 2 of my new DS lite?

What is this thing sitting in slot 2 of my new DS lite? ds lite gameboy slot Original Nintendo DS Lite DSL GBA Slot Cover 2 Dust Cover FREE SHIPPING *USA* Pre-Owned: Nintendo $ Free shipping ds slot I believe that the DS have some sort of software recognition in place to prevent DMG Game Boy and GBC games from

ds slot The Game Boy This cheat gets you infinite coins which can be used in the slot machine or exchanged for prizes such as Pokémon

ds lite gameboy slot The name dongle method is an unofficial name that comes from the fact that this method uses the Game Boy Advance game as a dongle for the Nintendo DS game  From Nintendo DS Accessories - Scott The Woz