This is a template attribute. Template attributes can be used in filtering, or to retrieve data from the model to use in drawings and reports. For example, when you create a report, Tekla Structures replaces the attributes added in the report template with the corresponding object property values.

These template attributes show special width values of some profiles. Below is an example of a parametric profile rectangular hollow section with subtype h1*b1-h2*b2*t, where b1 is WIDTH_1 and b2 is WIDTH_2.