This is a customizable key holder. Use the customizer app to modify the design to suit your needs. The size of the holder and screw size can be easily modified to suit different keys.

For this key holder I used #10-24 screws. I undersized the screw holes for this part so that they would thread into the bottom part of the key holder. This way no additional fasteners are required. I may add some Loctite or crazy glue to the screw threads to fix them in place.