units

meter	[‘m’]
milimeter	[‘mm’]
inch	[‘inch’, ‘in’]
international_foot	[‘foot’, ‘ft’]
us_survey_foot	[‘s_foot’, ‘s_ft’]
international_yard	[‘yard’, ‘yd’]
kilogram	[‘kg’]
pound_mass	[‘lb’]
newton	[‘N’]
pound_force	[‘lbf’]
kip	[‘kip’]
hertz	[‘Hz’]
radian	[‘radian’, ‘rad’]
arc_degree	[‘deg’]