Lid for the generic Steam Deck Carrying Case generic insert found on printables.  

[https://www.printables.com/model/249409-steam-deck-carrying-case-generic-insert](https://www.printables.com/model/249409-steam-deck-carrying-case-generic-insert)

Model is made to be tight so may initially have to be rough to take it off but it will get easier and fits very well. 

Does make the box stick out of the back of the case a little bit however by making the box smaller, it can fit perfectly in the back of the steam deck carrying case.