This thing is the signboard of a medicine man or a traveler, commonly called "tiger support". Baidu Encyclopedia explains: Legend has it that Sun Simiao, the king of medicine, was suddenly stopped by a tiger on his way to collect medicine in the mountains. The tiger was right in front of him, and it was impossible for him to escape. The king of medicine had a long flat stretcher with him for picking herbs, but it was not easy for him to deal with the tiger with this clumsy stretcher. He was at a loss for words, just staring at the tiger with fear. Strangely enough, the tiger did not pounce on him; on the contrary, it crouched on the ground with its mouth wide open, gazing at the Medicine King with a sad look as if it was begging for something, and gently bobbing its head. The Pill King was shocked by the scene before him, and he slowly approached the huge creature in front of him. He saw that a large animal bone was y embedded in the tiger's throat. The kind medicine king wanted to help him by removing the bone, but he was afraid that his arm would be broken if the animal suddenly shut up because of the pain. At that moment, he remembered a copper ring on his stretcher, and he took it off and put it into the tiger's mouth to hold it open, so that he didn't have to worry about his own safety any more. He passed his hand through the center of the ring into the bloody mouth and quickly pulled out the bone and numbly applied ointment to the wound. When the Medicine King removed the ring from the tiger's mouth, the tiger nodded his head as if to thank the kind doctor. From then on, the ring was transformed into a hand bell, which became the symbol of medicine collection. Doctors would take it with them when they went out to collect medicines to show that they were the disciples of the Medicine King, who was the only one who could treat the tigers and would not be attacked by them. In order to show that they also have the same medical skills as the famous doctor Sun Simiao, the wandering doctors also hold such an iron ring in their hands as a symbol of their medical practice, and named it Tiger Brace.