Private storage box

This is a private storage box with hidden compartments inside. There are no visible interfaces or screw fasteners on the outside. Usually, others can only see the small cavity inside, and only the owner knows that there is a hidden space at the very back. To open it, simply hold the metal cover and rotate the shell to reveal the innermost cavity, where you can store your secret money or important items. If you don't have a metal cover on hand, you can 3D print a cover to match.