The DFM DS steel fire-resistant doors are suitable for internal and external applications. The doors include aluminum door frames, stainless-steel hinges and other hardware elements, and unified thickness of door leaf for all fire ratings up to 120 minutes. The DFM DS doors offer low U-coefficients from 0.9 to 1.3 watts per square meter per Kelvin, and minimum maintenance due to Teflon hinge bearings and 40 millimeter gasket in the door frame’s extruded profile.