TPU slim wallet with a chain attachment

I really liked the original design, but for me it was lacking the very simple, yet useful thing - an ability to protect it from losing or falling out of the pocket. This can be simply solved by adding an attachable chain.

I created two variants of how this can be implemented, either with a simple loop attached to the corner or with a hole in the wall of the wallet, through which the chain or rope can be pushed. For the second design, I modified one of the corners' geometry slightly to keep it in the same style, but give enough room for the hole.
There are two variants of the hole, approximately for 2.5mm and 4mm. There are also .blender files in case you want to continue the tuning.

It might become a bit trickier to print, but I would recommend printing with the hole. At least my TPU gives impressive layer adhesion and material toughness, so it should hold the chain fine.