Abstract: The invention concerns an elongate decorative and/or protective covering strip particularly for the exterior of an automotive vehicle. The strip is a single piece blow molded strip with a bottom that is applied to a surface and a top that is exposed. To provide length compensation due to temperature variations as between the top and the bottom of the strip and to absorb expansion differences as between the strip and the vehicle body, the bottom of the strip has a plurality of transversely extending groove shaped depressions defined in it along its length. At least some depressions in the bottom of the strip are of a height to extend nearly to the top of the strip and to thereby support the top of the strip against deformation. The depressions may have various heights toward the top of the strip. Transversely extending depressions may alternate with round depressions along the length of the strip.