Cipher Ring V4 Box with secret Chamber

I made this box with a secret chamber for the "Cipher Ring V4" (https://www.thingiverse.com/thing:2706672) from @osj1961.

The cipher ring fits very well and tightly. If you take out the ring, you can also remove the centre part (core) of the box by a short turn. You can place a secret message or the decoding key in it.

I made the cipher ring and this box, as well as a multi-part encrypted riddle as a Christmas present. My nephews had to find out the password for a cryptex in several steps. One of the steps was to find the secret chamber where there were further hints.

Printed with wood (various wood filaments).
0.2 mm

(The lid of the lighter box on the images is slightly simplified because I had problems with the filament.)