D3643 Narrow Light Steel Door Door Type 3 Lock Type Mortise Material 16-Gauge Thermal Insulation U-Factor 0.41 Door Opening Height 80 in Door Opening Width 48 in Window Height 26 in Window Width 5 in Thickness 1-3/4 in Agency Compliance UL 1 1/2 Hour Fire Rating 7-3/8 in 37-5/16 in 67-1/4 in