Fit untwisted sealing ring on cover .

在盖上安装平展的密封圈。

Other filament yarn , single , untwisted or with a twist not exceeding 50 turns per metre , of polyesters , partially oriented , not put up for retail sale .

其他未加捻或捻度每公尺不超过５０捻之其他聚酯半延伸单股丝纱，非供零售用者。