Constructed using multiple layers of fire-resistant gypsum and mineral fiber insulation, cabinet body has a rugged powder coated steel exterior that provides excellent corrosion resistance. Under fire conditions, intumescent strips expand and hermetically seal all gaps to reduce heat entering the cabinet, providing 90-minutes of content protection and extended evacuation time. Hybrid style doors open or close manually and include a damper that adjusts the force needed to move the doors. In the event of a fire, the built-in fusible link system releases to allow automatic closure of doors at 122�F (50�C).