Depending on the make, model and type of vehicle, the opening at the rear of the vehicle has a rubber seal to prevent the ingression of air and water. boot tailgate rubber seal is specifically manufactured for the make and model of your vehicle. 

Normally  there is a rubber seal on the door and the door frame. The rubber seal runs around the door in a channel or protrusion which the seal is moulded to fit.

The construction of the rubber is semi tubular, when the door, hatch or bootlid is closed the rubber compresses and a seal is made with the frame.

Over time the rubber seal can become worn and the tubular section become punctured and torn. Replacing this part with boot tailgate rubber seal will ensure compatibility with the make and model of your vehicle.