Nothing fancy here: minimalist design, but functional.
It's a small box to store a 3.5 inches HDD. It just fits the drive, so it doesn't move.
I made two gutters to be able to place the drive with mounting screws potentially. With screws, the drive is even more blocked in the case.

This case won't protect the drive from shocks or other accidents, it's perfect for storage and to protect from dust and manipulations.

The box is just a little bigger than the drive itself, so for traveling, it can be placed in the original drive package !