A standard extension follows the line of the trailer (curbside or roadside). A wrap “turns the corner” around the front or rear of the trailer. It terminates on the opposite side. The photo shows a “rear extension wrap” turning the corner on the lift gate end of a semi.
The backdrop of an extension that reaches from the roof to the valance. On a tapered extension, it is shaped like a triangle. On a straight back rafter extension, it is rectangular in shape.
Extension back skirts zip to the extension back.
An extension adds to the length of the canopy by extending past the trailer end(s). The two most common styles are tapered (standard) and straight back rafter. The tapered style has a diagonal rafter extending from the trailer to the outside corner. The straight back style follows the same slope as the main canopy.
Extensions can be added to the cab end (front) or lift gate end (rear).