Left.SEDAN. Reinf plate rivet. Right.SEDAN. A fastener which consists of a shaft and a head on one end, and when the shaft end is installed it exPands and holds the Roof Panel Reinforcement. 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. Quarter lock. REINFORCED plate. Roof Reinforcement. Uniside.