This is a casing for 25mm round NFC tags like these ones.
This has two halves that you superglue together with the NFC tag inside.
I printed this in transparent Elegoo smoky black resin. Anything transparent should work.
There is a storage tray for them here.
Printer: Elegoo Mars 2 Pro
Supports: Yes
Resolution: 0.05mm (50μm)
Material: ABS like, but anything rigid should work
The author marked this model as their own original creation.