Defining filters for displaying alternate UOMs
Users can see an alternate unit of measure as a default value. In this case, you must assign the parameter to a filter with the new unit of measure. Otherwise, the base UOM displays by default. And the value that is stored in the database is the base unit of measure for the parameter.
See Specifying an alternate unit of measure.
When users select the filter in an item, formula, specification, project or comparison, the unit of measure is that of the filter. Any values that were previously specified with another filter are converted.
In this example, the default unit of measure is inches.
The alternate is centimeters.