二级头 èrjítóu second stage Definitions Defs Origin Strokes Stroke Words Sentences Sents 二级头呼吸器 èrjítóuhūxīqì regulator (scuba diving) regulator; demand valve备用二级头呼吸器 bèiyòng'èrjítóuhūxīqì octopus a backup regulator used in scuba diving, often referred to as an octopus
