The whole body is made of bronze, disc-shaped, the central protrusion is hemispherical milky, the surface is not flat, and there is a circle of protrusions on the edge. Terbium bodies are of different sizes and have many specifications.

Common thu can be generally divided into three types: large, medium and small. The diameter of the large navel is 40 cm, the side width is 6 cm, the diameter of the breast navel is 7 cm, and the breast height is 5 cm; the diameter of the middle noodle is 30 cm, the side width is 5 cm, the diameter of the navel is 6.5 cm, and the breast height is 4 cm; the diameter of the small noodle is 30 cm. 20 cm, side width 3.5 cm, milk diameter 6 cm, milk height 3 cm. The height of the protrusion on the edge of the surface is 0.5 cm to 1 cm, and the tether is drilled on one side of the edge. In addition, the smallest one has a face diameter of only 9 cm and a side width of 1 cm, and the pitch can reach a2; the largest one has a face diameter of 72 cm and a side width of 14 cm, and the pitch can reach F or G.

The Chinese Musical Instrument Museum of the Institute of Music of the Chinese Academy of Arts in Beijing has a collection of dozens of facets, the smallest with a diameter of 15 cm and a side width of 3 cm; the largest with a face diameter of 67 cm and a side width of 11 cm. Two of them have been included in the large-scale catalogue of "Chinese Musical Instruments Illustrated Guide". In the 1950s, among the Zhuang and Yi folks in Mengzi County, Yunnan Province, a concave breast shaped special-shaped dagger was discovered, that is, the center of the breast navel was concave inward, and the percussion direction also changed. The quality of erbium should be accurate in roundness, uniform in thickness and radian, smooth in surface and bright in tone.