A mechanism of low cost and easy mounting, provides resistance to rotation of a coupling nut of an electrical connector about the barrel of the connector, and provides a higher resistance to rotation in one direction than the opposite direction. The bending apparatus includes a central retaining portion that has gripping elements mounted on the central retaining portion for retaining an aluminum metal sheet. Further, alternating steps of reactive ion etching and ion beam etching are performed to isolate MTJ pillars and expose side surfaces of the MTJ layers. A collector panel, which is separated from the interior panel to define a heating chamber, is exposed to, and heated by, solar radiation.