Before the advent of spring-activated weighing machines with dial faces, the “dacing” in varying sizes, was universally used in all kinds of retail business.
It was also widely known that sellers sometimes manipulated the implement to cheat customers either through deft handwork while shifting the counter-weight, or by stealthily pre-loading the weighing pan (a favourite technique was to coat the underside of the pan with assam paste – thus gaining several tahils’ worth for the seller).
Our family used to have one set at home, with which we re-weighed everything we bought. The neighbourhood sundry shop knew we had this Weapon of Mass Discernment and wise enough never to have tested its awesome power. In fact, the proprietor always added a little bit more to what we asked for, as a “safety margin”.