Box for play/teaching cards with pen compartment

This is a box for laminated exercise cards for use in elementary school. The compartment for the cards features bumps at the bottom so that the cards don't simply float around and there is an extra compartment for erasable pens to write on the cards.

If it's interesting to anyone I'll upload versions with custom dimensions or a customizable thing altogether.

Main compartment is 145mm wide and 90mm long. The extra compartment is 15mm wide, overall height is 75mm.