Id Ml Name Symbol N Basis Reference
SY5 inch-pound ip NIST Special Publication 1038
SY4 uk-imp UK-Imp
SY3 us-imp US-Imp
SY2 imp Imp
SY1 si SI 7 (AS2,SC1), (AS3,SC2), (AS4,SC3), (AS5,SC4), (AS6,SC5), (AS7,SC6), (AS8, SC7) SI Brochure