On an automobile, a quarter panel (or rear wing in the case of a rear quarter-panel) is a body panel that covers the section between the rear door and the trunk, or the front door and the hood. It is typically made of sheet metal, but is sometimes made of fiberglass and fibre-reinforced plastic. They are the parts of the exterior of the car that are left once the hood, trunk, roof, doors, bumpers, fenders, lights, and plastic trim are taken away. It typically wraps around the wheel well. Damage to one of these panels does not affect the frame, so this panel can be replaced with little effect on a vehicle's safety and crash worthiness.
This panel is designed differently for various types of vehicles. Hence, for every car, the panel has different sizes and lengths to where it may extend. As shown in the image, it is not forming a part of the upper body. This type of design is very simple to replace in case of damage. The others extend themselves close to the front door from top and bottom. There is a cut generally visible if you follow the part line till the front door to reveal a 'C' shape. These 'C' shaped parts are hard to replace as this involves removing the windscreen among other tasks.
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