This bi-fold door features a retractable door width structure. When folded, each door measures 6.5 ft. high by 0.5 ft. wide, and when expanded, it can reach 6.5 ft. high by 12 ft. wide. It is suitable for security doors, roadblock doors and defense facilities. The door body is made of heavy-duty 3/4 in. 14-gauge channel steel, which is powder-coated black for durability and anti-tampering. The bottom is equipped with 360° rotating rollers and locks for flexible opening and closing and ensuring stability. The included padlock hasp, padlock key and installation tools are convenient for secure locking and easy installation, effectively protecting your property from intrusion.