This is a sequential discovery puzzle box with two internal compartments requiring 23 moves to fully solve.

This is one of my most difficult pieces to print due to some extremely fine details on some pieces (particularly the gear set). I would recommend printing the Gear, Rack & Pinion pieces (and maybe the two slider pieces) with a 0.25mm nozzle or smaller to ensure they function correctly, or upsizing the entire piece if you don't have a smaller nozzle.

All pieces are designed to be printable without supports, but the Slider(C) and Core could potentially benefit from them. The Core though could be difficult to remove supports from - I would recommend trying without first if your printer is at all capable of handling bridging.

Lastly the Core has two places I added a thin horizontal layer (0.25mm) to allow it to print better which must be broken through before assembly. See the second image attached for locations - this picture is taken on the 22.4mm layer.

Pieces marked with (C) should be printed in color, while the (B) pieces should be printed in black. The ones without a designation are not visible when fully assembled.

As with all my puzzles I recommend using a couple of metal files to smooth down any rough edges and account for printer variation when assembling.

Assembly steps:

1. Clean/File all pieces - this includes removing the thin layers, and filing down various faces of the gearset (if gears don't move smoothly, printing these pieces on a slightly reduced scale might help)
2. Put Gear in slot in Core - check to ensure Gear rotates smoothly
3. Put Pinion through - check to ensure gearset rotates smoothly
4. Insert Drawer
5. Attach Four
6. Attach Six
7. Insert Rack through hole in Six - check to ensure Pinion flat side is out
8. Combine Sliders and Three and attach
9. Combine One and Lid and attach
10. Insert Rod through hole in Six
11. Attach Two
12. Combine Dot and Five and attach
13. Attach Stopper

Update: I added a "Core(Supports)" .stl file which removes the thin layers hopefully helping in assembly. I have also made some adjustments since then, so any reprinted Core files will need reprinted Five, Six and Dot files as well. I also updated the Slider(B) file to be a little tighter.