The maximum physical media size across the feed direction of
this media path expressed in units of measure specified by
prtMediaPathMediaSizeUnit. A value of (-2) implies 'unknown'.
Additional information:
The values returned by these objects depend on the value
of prtMediaPathMediaSizeUnit. It is 85000 if prtInputDimUnit is
ePtenThousandthsOfInches or 216000 if prtInputDimUnit is ePmicrometers.