

celsius = 'celsius'
fahrenheit = 'fahrenheit'
kmh = 'kmh'
ms = 'ms'
mph = 'mph'
kn = 'kn'
mm = 'mm'
inch = 'inch'
iso8601 = 'iso8601'
unixtime = 'unixtime'
utc_offset_seconds = 'utc_offset_seconds'

