Marble relief, circa 130 CE (Dresden, Skulpturensammlung [Albertinum]) Inv. No. 415. Photograph: DAI). Compared to equal-arm balances, unequal-arm balances have several construction-related disadvantages but also many advantages. As no set of standardized reference weights is needed, they are well suited to transport, for example. It appears that large specimens in particular were also sometimes set up as stationary devices, as on the relief shown here, which depicts a Roman butcher at work.