Nothing on the bottom or sides. Nothing in the manual. It may be as Jim says and it is electronic. It is weighing within one gram more or less when tested with a reference weight.
It isn't so much that I need to calibrate this one now, but I need to buy a 600 gram weight to calibrate my smaller jeweler's scale that I use for cure and mod ingredients, so I wanted to buy whatever this scale needs at the same time. Amazon doesn't have good choices, so if am buying from a specialty retailer I wanted to do it at once.
FYI,
http://www.oldwillknottscales.com/ had the best prices on calibration weights that I could find, in case anyone else is interested.
Thanks,
--Lisa