exactly what I thought.It looks a bit like a calibration weight. The construction is different than ones I have seen though and the 106 is an odd designation.
Have you tried weighing it to see if it is a standard value or perhaps 106g?
I could be wrong but I would guess the hole is just there to allow pressure equalization so that the tight fitting lid can be used.
Have you tried removing the stem? Are there any clues inside?