The corrugated medium and linerboard board are made of kraft containerboard, a paperboard material usually over 0.01 inches (0.25 mm) thick.
The panels contain cells made in China, Taiwan and, sometimes, Germany. Grape still plans to import inexpensive Chinese-made cells, and to buy Oregon-made inverters -- which convert direct current to alternating current -- for the panels it assembles in Eugene.
Due to the low voltage of an individual solar cell (typically ca. 0.5V), several cells are wired (also see copper used in PV systems) in series in the manufacture of a laminate. The laminate is assembled into a protective weatherproof enclosure, thus making a photovoltaic module or solar panel.