A steel door is a type of door made primarily from steel, known for its strength and durability. These doors are commonly used in commercial buildings, warehouses, and residential properties for security purposes. They can withstand harsh weather conditions and resist forced entry, making them a popular choice for safety. Steel doors come in various designs and finishes, allowing for aesthetic versatility. They can be insulated to improve energy efficiency and are often equipped with additional features like locks and frames for enhanced security. Overall, steel doors provide a reliable solution for both protection and functionality.