Aperture panel nut. Left.COUPE. Right.COUPE. A nut used to retain the Body A-Pillar to it's mounting point. A solid metal or plastic block with a threaded hole in the center which is used to tighten or adjust the Aperture Panel. A solid metal or plastic block with a threaded hole in the center which is used to tighten or adjust the Quarter Panel. Aperture. Body A -. Hinge. Quarter. Uniside. Included with: Hinge pillar, Quarter panel.