Now that I never need keys with me as almost everything is digital, I still wanted my house key with me just in case. I created this to stash my key in my wallet without worrying about it falling out. I suggest printing in natural (clear) as it's cool and you can see the key is in there.

The STL is both halves but I can split if somebody can't print both half's together. It's sized to be the same size as my credit card and to hold a 2.3mm thick key that is 54mm long and 23mm wide. The cutout is similarly sized as the key to limit the rattling. I may add to the thingiverse customizer but for now I can create a new key size if needed. Please ask!