Cooper B-Line B556 Series five hole corner gusset plates are designed to strengthen the corners of metal frames, brackets and supports, providing added rigidity and load-bearing capacity to the structures. They are used in construction applications where structural stability and reinforcement are required. These gusset plates are made of ASTM A1018 steel with Dura-Green finish for providing corrosion resistance and strength. They have five holes with 9/16 inch diameter, allowing easy attachment to the beams or structural members.