National N351-500 4.9" X 3" X 1/8" Structural Corner Brace - Black. (1156BC) Used for reinforcing 90 degree angles by applying to the inside or outside of the corner. Slots for 1/2" Carriage Bolt. Larger bolt holes provide options for structural support. Chamfered corners provide decorative look. Black powder coat finish for improved weather resistance. Warning: The safe working load for this product depends upon the application and fasteners used. In order to reduce the risk of personal injury or property damage, consult with design professionals to determine if this product is appropriate for your application.