mass unit prefixed gram prefixed tonne prefixed unified atomic mass unit unit 単位 International Unit 国际单位 carat (mass) karaat (massa) grain gram gram 克 hundredweight (British) hundredweight (US) milligram RAE ounce (apothecaries') ounce (avoirdupois) pennyweight (Troy) pound (apthecaries') pound (avoirdupois) slug 金属块 solar mass zonsmassa ton (long) ton (short) ton (short assay) tonne ton 公吨 unified atomic mass unit