Two crude Chinese characters - Ban Liang ("Half an ounce"), no rims or other marks / Blank, no rims. Unfiled edges. 18mm, 0.71 grams. Gratzer/Fishman #12.24. SKU T1051-13652.

This very small coins of variable weight were cast during the inflationary period under Er Shi Huangdi, the second and last Emperor of the famous Qin dynasty. 

This coin is unconditionally guaranteed to be authentic.