Group of three shooting rings (“ban zhi”) in hard stone

Three cylindrical archer rings, one in green stone and two in white stone with yellowish pigmentations. Smooth surfaces, with minimal abrasions.
中国 二十世纪硬石扳指 三件组 含一件绿色石质扳指及两件白石带黄色纹理扳指。表面光润，略见细微磨痕。

diam from 3 cm to 3.8 cm