qiānyǐn guāngshù

== Mandarin == === Romanization === qiānyǐn guāngshù (Zhuyin ㄑㄧㄢ ㄧㄣˇ ㄍㄨㄤ ㄕㄨˋ) Hanyu Pinyin reading of 牽引光束 / 牵引光束