Two purposes are served by this little lifehack gadget: It is the casing for a single ID-1 card with standard dimensions as well as the little box for additional objects.
For instance, it can accommodate the RFID key card and the standard key if it is practical to hold both access keys together.
Bridging precision of your printer is crucial for this design!
Please note that the entire space for the ID card is bridged since no support is possible in here. Make sure your slicer does not introduce a supporting material.