Copi-Counter
A gift from a friend in the printing side of the publishing industry, this doohickey is similar to a rolling ruler or map measurer, but it's calibrated for units of measurement only used in the printing industry - picas on one side, and agates on the other. I suppose this isn't strictly horology-related, but similar pieces were often, unsurprisingly, produced by companies producing pocketwatches (e.g. Hamilton), and it's got dials and two lovely blued hands and a bunch of nifty little gears, so it's close enough for me.