UNITS allows you to specify scaling units for dimensioning
other than the units used in the construction of the part
itself.

The construction unit switch indicates whether working
units (for geometric construction and so forth) are
interpreted as inches, millimeters, feet, centimeters,
yards, or meters when displaying viewing scales, creating
plot files, and working in conjunction with the UNITS
function. When an option is selected, the unit of
measurement designated is applied as a scale to all
dimensioning thereafter. All previous dimensioning remains
the same.

Assign a unit by choosing from the following options:

INCH  - to assign inches as the scaling unit
MM    - to assign millimeters as the scaling unit
FEET  - to assign feet as the scaling unit
CM    - to assign centimeters as the scaling unit
YARD  - to assign yards as the scaling unit
METER - to assign meters as the scaling unit
USER  - to enter your own scale factor for the current 
        part

USER lets you enter a custom scale factor for the current
part units. Enter a new value, or press <Enter> to accept
the default scale factor. CADKEY multiplies the new value 
by the dimension unit value and displays it as the new
dimension.
