My wife bought a kitchen "multi measure," which is just a shot glass with
numerous graduations on the side. I checked its accuracy as best I could
with a 100 mL graduated cylinder. The metric scale (mislabeled "ML") was
pretty accurate, certainly enough so for cooking purposes.
It has three colloquial scales: teaspoons, tablespoons and ounces.
Interestingly, the teaspoons and ounces were accurate, and 6 tsp = 1 oz,
but the tablespoon scale was significantly offset. It was made in China,
so maybe (hopefully!) they don't have a clue that all three could use the
scale.
Jim Elwell