Roof corner cap.
This cap fits two corners. If you were to draw an X in the center of your roof, each end of each line of the X would reach to the same cap.
Black plastic. Paintable.
Add a corner cap installation kit here
Directly compatible for metal roof units produced after 2006.
These caps are today's closet match to the original completely smooth versions. Two height options were available originally, this cap is the 11-3/4 inch height. If your unit has the shorter version, the extra material would need to be removed from the bottom of the cap. The profile at the top of the cap will sit just a bit higher than the original as well, some extra tape and caulk should be applied to this area.
Installation instructions and images can be found here
Measures 11-3/4 inches tall by 2 inches wide on each side.
Part number 4701-0512