2.5% Tung tubes (Non code) with TA liner silver brazed to tube sheet, glass lined carbon steel heads (tubes are roller expanded into grooves and seal welded to tube sheet face) 8 x 4 concentric reducer on one end and 8 x 4 eccentric reducer on other end. 4" thick foam glass insulation covered with 12 GA 316 L sheathing on the shell side only. Sheathing has a 50 RA finish with vent & drain. Six, PTFE Teflon (1/4" thick) baffles @8" spacing face to face.