Abstract: Decorative plastic welt has an elongated, decorative, arcuate, bead portion formed of a first plastic material. An integral elongated plastic flange extends from said bead along its length to an outer flange edge and defines a first flange portion adjacent the bead and a second integral flange portion extending from the first portion to the flange edge. The second portion is an elongated see-through plastic strip which permits the flange to be aligned with sheet materials on either side so that positioning notches in the sheet materials can be matched by visual observation through the strip.