Dr. Kenoyer writes of this distinctive ancient Indus object (Ancient Cities, p. 145-46).
"However, one style of bangle was always made the same size, between 5.5 and 6 cm interior diameter with a highly burnished surface fired to a red or a gray black color. Generally referred to as stoneware bangles because they were fired at very high temperatures, these standardized ornaments were almost always inscribed on the outside edge with minute signs of the Indus script (fig. 7.47). Relatively few stoneware bangles were made, probably to be worn as a badge of office or ritual ornament. Since they were made in standardized sizes that would not have fit a large hand, it is possible that they were attached to a necklace or worn in the hair instead."