This 3D printed cartridge case is for the Atari Ultimate cartridge that is compatible with the Atari 1200. This is an SD based cartridge interface that allows programs to be loaded off SD card as though it were connected to one of the old legacy drives. Similar to the 1541 Ultimate device for the Commodore.
Please take note that this is for the cartridge case only. You will need to obtain one of these devices for the case yourself. They are available from time to time on http://atariage.com/forums.
This cartridge case has had it's physical outside dimensions altered to be compatible with the Atari 1200. This version of the case is also compatible with the Atari XL/XE machines.
The case is available in a variety of colors.