14 gage steel face sheets, cold-rolled or galvanized Vertical steel-stiffeners, spaced 6" apart, welded every 5" Non-combustible Fiberglass Insulation "R" factor: 1.626 (Reference: 1" Thermal Pane Glass = R 2.0) "U" factor: 0.615 "STC" (Sound Transmission Class): 38 Integral Flush Welded Glass Lite Trim Kits Recessed Steel Top channels - Welded to both faces for added strengthwith optional steel closing cap. Hinge reinforcement 7 gage steel (3/16" plate). 12 gage Closer Reinforcement plate optional Galvanized stiffeners optional 12 gage Welded Frames complete range of sizes and profiles Cold-rolled or Galvanized Steel