The Atari UNOcart from The Brewing Company is an Atari cartridge emulator and XEX file launcher. When purchased from the vendor, the cartridge board is wrapped in minimal protective shell (presumably for shipping purposes) that works well for protecting the board during shipping but does little for protecting the board during use.
This is a proper cartridge shell designed specifically for this cartridge board. Once installed, this cartridge can be plugged into any of the Atari 8-bit line of computers including the Atari1200XL. Yes, it is compatible with that cartridge opening as well!
The case is a two piece design, with four brass heatsets embedded into the lid, and held together with four black oxide hex-key screws. Openings in the lid exist to allow access to the microSD card, visual access to the onboard LEDs and of course the onboard push button!
UNOCART is embossed on the lid.