These are your Customers Unique IDentifier. The field(s) that are used outside your company. This is a new umbrella term for the existing class of identifier that was previously the primary user facing representation of uniqueness.
So for example-
- PQR #
- WPS # when combined with WPS Rev #
- WPQ# when combined with WPS #, WPS # Rev, Welder Identifier
- Welder ID
This new structure allows duplicate CUIDS so something like a tracking number that your customer "John Smith Co" demands be on "WPS 1" while "Pyramid Co." demands a different value be on "WPS 1" can be accommodated. Those 2 companies requirements may directly conflict or "WPS 1" may have already been in use in its present form and should be kept in that exact state permanently but the new company wants some change that, though not impacting on qualification, is an alteration and they still require the same WPS number and revision as was originally submitted to them in their documentation.