File referenced by GBA4iOS, a Game Boy Advance emulator for iOS devices; contains controller configuration information; customizes the skin, or appearance, of the Game Boy Advance controller used to play Game Boy Color games on your iOS device; similar to the .GBASKIN file, which is used for playing Game Boy Advance games in GBA4iOS.

To change skins inside the GBA4iOS app, select the gear icon in the top-left corner, go to the "Controller Skins" section, tap "Game Boy Color" or "Game Boy Advance" (depending on which skin you want to change), select either "Portrait" or "Landscape" (depending on your desired orientation), and select the skin you want. NOTE: You can download GBCSKIN files through the GBA4iOS app or you can go to Game Boy skin websites, download the skin(s), and manually import it into the app.