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.
NUMBER shows the revision number in Rev.No. box in the Revision handling dialog.
NUMBER#1 shows
the total number of objects on a list. NUMBER#1 also shows the total
number of parts and bolts for one assembly for list types ASSEMBLY, ASSEMBLY_BOLT, ASSEMBLY_PART, and ASSEMBLY_ALL, if the object is
part of an assembly on the list.
NUMBER#2 shows
the project
number as text.
For spiral reinforcing bars, use the ROUNDS attribute to show the number of rounds.