Jamieson, Fausset and Brown on Deuteronomy 25:13-16

13-16. Thou shalt not have ... divers weights--Weights were anciently made of stone and are frequently used still by Eastern shopkeepers and traders, who take them out of the bag and put them in the balance. The man who is not cheated by the trader and his bag of divers weights must be blessed with more acuteness than most of his fellows [Roberts]. (Compare Pr 16:11; 20:10).