Turning a DS Lite into a Game Boy Macro creates a dedicated device for playing Game Boy Advance games only. So we created a 3D printed cartridge to fit into the Nintendo DS game Cartridge slot on the Game Boy Macro. Acting as a dust cover and placeholder. It also fits into other devices such as the Nintendo DS, DSi, DS Lite, and the DSi XL.
These carts are PLA+ 3d printed @ Retrosavers.