Used 765 Sq Ft. U-Tube Heat Exchanger. Mfg by Heat Transfer Equipment 1980. Carbon steel Shell (SA-516) rated 150 PSI @ 500 deg F; Carbon Steel Tubes (SA-53-B) rated 150 PSI @ 500 deg F. Carbon Steel Heads (SA-515). Shell - 2'2" dia. x 21'9" L ; (204) Tubes - 3/4" dia. Flanged Nozzles: (2) 12", (2) 6". S/N: 80-855-B, ASME Rated. No NB #.