The caliber is 2.3cm and the weight is 25.9g. It is a special object used to protect the archer's thumb from being strangled by the bowstring. In the and Qing dynasties, it gradually evolved into something for the nobles to play with. Various regulations in the became more and more perfect. Although the fingers were small, they were also a symbol of strict hierarchy. They were mostly made of precious materials such as jade, jade, agate, and coral. Non-royal princes were afraid to wear them at will.