L-trim is a type of trim used in the construction of metal buildings to create a clean, finished edge where two surfaces meet at a 90-degree angle. Its name comes from its L-shaped profile when viewed from the side, with one leg of the "L" designed to cover one surface and the other leg designed to cover an adjacent surface. L-trim serves both functional and aesthetic purposes, providing a neat, polished look while protecting exposed edges. The L-trim acts as a protective barrier, covering the edges of metal panels or other materials. It prevents moisture, dirt, or debris from entering the gap between the metal panel and the building, which helps avoid rust or corrosion over time.