From the outside the Pen Cup looks completely normal. The secret Case can only be opened with the Magnetic Opener.
12 small round magnets are required for the Pen Cup.
Size: 6x2mm (diameter: 6 mm | thickness: 2 mm)
Amazon: https://www.amazon.de/gp/product/B07RT9MY52/ref=ppx_yo_dt_b_asin_image_o01_s00?ie=UTF8&th=1
I recommed using black PLA.
Less Support-Structures are required.
Credits:
Aropix