D3651 Narrow Light Steel Door Door Type 2 Lock Type Mortise Material 18-Gauge Thermal Insulation U-Factor 0.41 Door Opening Height 84 in Door Opening Width 36 in Window Height 26 in Window Width 5 in Thickness 1-3/4 in Agency Compliance UL 1 1/2 Hour Fire Rating 4-7/8 in 37-1/8 in 69-3/8 in