Abstract: A boot/trunk opening in the vehicle body has a flange to which a looped sealing strip should be attached. However, when the boot/trunk lid is fixed to the vehicle body by hinge arms, these hinge arms prevent a pre-formed loop-shaped sealing strip being satisfactorily fitted to the flange. Disclosed herein is a sealing strip having a heat-bonding air-permeable foil attached to one end thereof. A sealing strip of this type can be supplied in strip form and threaded between the hinge arms and the vehicle body. The end of the sealing strip to which the foil is already attached is then bonded to the other end of the sealing strip by a bonding operation performed at the vehicle to form a looped sealing strip. An apparatus and method for performing this in situ bonding operation is disclosed. Apparatus for forming a sealing strip with a foil attached to one end thereof is also disclosed.