A ringer used by ancient patrols or yamen to collect and disperse people's knocks. Made of bamboo or hollowed out wood. The second chapter of "Water Margin": "In the front and back of Zhuang, Zhuangdong and Zhuangxi, three or four hundred Shijiazhuang households heard the sound of bangs, all dragged guns and sticks, gathered three or four hundred people, and all went to Shijiazhuang ." ...