Plain cong of this type that appear to be made from similar stone were made in different sizes and with collars of different heights. One ( 8.7 cm. high) from Shaanxi province, dated possibly Neolithic or Shang period, c. 2000-1200 BC, is illustrated by J. Rawson in Chinese Jade from the Neolithic to the Qing, British Museum, 1995, p. 151, fig. 2. Two others in the Grenville L. Winthrop Collection are illustrated by M. Loehr in Ancient Chinese Jades, Fogg Art Museum, Harvard University, 1975, pp. 278-79, nos. 406 (7.5 cm. high) and 407 (5.5 cm. high). Both of these latter examples have similarly shallow collars and wide central opening.