A small wooden box with a mirror?

there was really no good way to word this question. basically, when i was a little kid in elementary school, my teacher did this thing where she brought out this really small wooden box. she told us all that when we looked inside, we would see something very special. there was a mirror on the inside, and the special thing she was refering to was us. anyway, i want to get something like this, but i cant seem to find anything like it. i could really use some help. thank you