It's just an insert for the boardgame Terraforming Mars that fits all expansions except for the big box addons, including the deluxe boards and premium sleeved cards.
Everything fits according to the images, if you don't have the deluxe boards you'll need a filler to compensate their space (I recommend using foamcore to fill that space).
This insert was designed to fit everything in the base box without lid lift and with the least amount of plastic possible.
Print the the amount indicated on the file name (x1, x2 or x3)
Happy printing!
The author marked this model as their own original creation.