Hazardous material identification number card storage box

Background:
I've designed this storage box for a friend who works as an international truck driver, he deals with hazardous chemicals and he needs to have these standardized ID cards on hand to signify what he's transporting.
There wasn't a good storage solution at hand so I designed one for him.
It features a magnetic latch, 12 slots to fit up to 5 cards each (0-9, X and blank) and there's an optional handle so you can easily carry it around.

Warning: this print is pretty big and costs a lot of filament.

Required materials:
12x 6x1mm magnets
A tube of superglue
2x100mm steel wire or 1.75mm filament for the handle (optional)

Print instructions:
0.16mm height, 3 walls, 3 top/bottom surfaces and 30% infill, no supports needed!
I used "cross zag" from the latest orcaslicer release. I printed this in PETG because it needs to withstand some impact because it's going to live inside a truck storage compartment. The numbers didn't survive my print, but that was because I accidentally ironed that surface as well and they all fell off, so don't be like me and only iron the topmost surface of your 20hr print. :)

Installation instructions:
All you really need to do to use the card box is to install the magnets, there's 6 slots on each side, make sure you align them before installation, give it plenty of time to cure before using it.

If you don't like the magnets (I found them a bit weak) you can also print some solid 6x2mm cylinders and glue it into one end to function as a dowel.

For the optional handle, you need to use a piece of wire that goes through one side to the other, you can use a soldering iron to melt some filament into the holes on each end to keep it in place. 
Protip: While the filament is still hot, use the top end of a steel bolt to iron out the surface for a smooth finish.