Mediocre's SD Storage Box

This is a small box with a sliding lid for holding up to 9 micro-SD cards.Many 3d printers or cameras use these, so it can be useful to store and organize them. I picture this primarily as a desktop usage, as there is not currently active retention of the lid. There is a rudimentary organization system incorporated into the design:
There are 3 clusters of 3 slots, each with the three shapes, Triangle, Diamond, Pentagon.
If you remember the shape and cluster of the slot you used, you should be easily able to retrieve the exact one you want.

I encourage feedback and remixes, and open the challenge to design the simplest active retention modification. Have fun, I hope someone finds this useful.