These are the most proven, cheap and powerful space grade silicon solar cells in the market, with a titanium oxide and aluminum cover glass and cell interconnects (3) installed, they have been flown many times in many cubesat missions. They are very tough, proven survivavility of 10+ years with a reasonable EOL degradation level due to its coating, they have multiple points linked to the substrate, even a broken in half cell keeps working if properly installed. We have a 300+ units in inventory.