This side-knife overlay attaches to the outer end of the cutterbar on a grain-harvester header. It provides a replaceable wear surface that protects the underlying knife section from abrasion and impact during operation. As the knife reciprocates, the overlay contacts the stationary guard, and wear on this face eventually reduces cutting efficiency and increases the gap between the knife and the guard. Replacing the overlay restores the original cutting geometry without requiring a full knife-section change. The overlay is manufactured to the same profile as the original assembly, so it seats correctly against the knife back and the guard face. On installation, ensure the mounting holes align and secure the overlay with the specified fasteners.