This is a vintage balance scale. The device was made at the Nizhny Tagil Medical Instruments Plant (Russia) in 1961. The measuring tool was designed for weights from 0,03 oz. (1 g) to 0,7 oz. (20 g). All this information is on the arms of the balance (photos 3, 4). The manufacturer's marking is on the left arm.
The weighing pans are made of black bakelite. Their diameter is 2,4'' (6 cm). On the bottom each one has a number '1' and '2' (photo 6). These numbers should be matched with the same ones on the arms of the balance. The pans are suspended with the green threads. Regulating the length of threads you can make the two pans hang even.
Length of the beam is 5,5'' (14 cm).
The pan balance is in very good condition. There is no rust or any other signs of damage.
The balance scale was the first and the simplest mass measuring instrument. It was widely used as far back as about 2000 B.C. And until 17th century A.D. all the weighing scales only were variations on the balance scale.