Does “area of validity” here refer to NRW or two specific points only?

I have a trip from Hamm Hbf to Wuppertal Hbf. Am I only allowed to use this ticket in the area between these two points, or can I go to other cities further than Wuppertal, like Solingen. I’m assuming this ticket allows me to travel further and to anywhere in NRW I want, but I just want to be sure.