My F150 key was so old that the keyring attachment broke off. I think this must be a common problem because my other key for this truck did the same thing. So this fixes that problem by encasing the key in a 3d print, giving it back a key ring attachment. 

How to use: 

Put a pause in your slicer before the gap inside is closed and insert your key, then resume the print. If you use the included 3mf file, the pause is already included.