<http://schema.org/description>
"&lt;p&gt;Many of the gaging applications we've considered over the years involve size inspection of a single feature, that is, the diameter of a hole, depth of a groove, height of a gage block, and so on.  Many parts, however, contain multiple features that establish dimensional relationships between two or more other parts. &lt;/p&gt;"^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.mmsonline.com/columns/gaging-distance-between-hole-centers>