D3706 Narrow Lite Hollow Steel Door Door Type 3 Lock Type Mortise Material 18-Gauge Thermal Insulation U-Factor 0.41 Door Opening Height 84 in Door Opening Width 48 in Window Height 29 in Window Width 31 in Thickness 1-3/4 in Agency Compliance ANSI A250.8-1998 UL For Use With Frames 3TFZ1 3TFZ3 3TFZ5 3TFZ7 Includes 1/4 in Clear Wire Glass with Safety Film Fire Rated For 90 Minutes 7-3/8 in 39-5/16 in 71-1/2 in 39-15/16 in 84 in