This is a Key Ring / Key Holder that is designed like a Swiss knife. I've made a key holder for different type of key to hold inside while it can be turn out by the outside detail. (You can edit the profile using the STEP file if it does not fit.) Also, I've made the pin to be a tight fit with the holes on the cover so that it can be fit without screw. But if your printer can not print it very tight, you can use washer screw to tight them together. Or you can print the washer and tight them by normal M2.6 x 6mm screws. I've upload a STEP file also. If you want to insert more keys, you can extend the pin in CAD also