Something not really mentioned, but like all the major components on a panel, are fundamental to the overall performance. And they take the full brunt of the sun everyday!
The panels here are having an expoxy coat applied to them, after what appears to be warranty issues. Some faulty batches of panels with backing film issues were sold in 2012, and Trina being a respectable company, is shown here fixing the issue.
Sometimes, paying a tiny amount more for major brands is very important it would seem.