Door Back also referred to as the fifth door, lid, and gate is the trunk door. This gate is used to open and close the behind of the car. It is made of the same material the body of the car is, and is painted in the same colour. The door back is also equipped with the lights in some vehicles, and the wiring runs from inside the door. This door back, is the entrance point of the trunk, which is a huge space at the back end of the car. This door works the same way other doors of the vehicle does. This door is solid, and can protect as much as the side doors can. The design and the shape of this back door is different than other doors of the vehicle, as it is designed to provide as much luggage space as possible, while ensuring that the shape of the vehicle matches.