Box with 16, 13mmx13mm slots.
I produced this to hold those Albuterol tubes used in nebulizers, but I suppose it can double as a holder of pens and the such.

Note: If you intend to use for the same purpose, please keep in mind that most of the time this medicine comes packaged in packs of 4 or 5 and in foil; the instructions (on my specific foil package) states that, once opened, the medicine should be used within a week.

I note this because I made the 16 slots and loaded them all up with medicine BEFORE reading the packaging/instructions and will likely lose more than half the batch.. lol