Another name is 4.14-meter Refined Steel Spear. It's a long spear of about 4.14 meters with a serpent -like head.
Zhang Fei was the wielder of the Serpent Spear. It was made with the weapons of his two brothers. He kept it with him during all of his numerous battles. After quelling the Yellow Turbans, the next major conflict it saw was against the mighty Lu Bu. Zhang Fei was the first to ride out and meet the challenge. Despite needing aid from his brothers, he became renowned as a warrior. Zhang Fei even deterred Cao Cao's fearsome legions with a loud roar. The other great duel that this weapon participated in was against Ma Chao. Zhang Fei had his weapon until his death. After that, it was passed to his son, Zhang Bao, and used in Zhuge Liang's northern expeditions.