Flexible CAB (cellulose acetate butyrate) plastic trim cap that caps the perimeter of a channel-letter face and locks the acrylic face to the metal letter return. The cap is glued and stapled over the return edge, concealing the seam and outlining the letter, the colored plastic is extruded around an aluminum core and is UV-stable for exterior service. Supplied on continuous reels. Recommended for channel-letter and dimensional-sign fabrication.