Used 400 Sq. Ft. Horizontal 316L-SS Shell and Tube Heat Exchanger. 316L-SS Shell Side rated 75 PSI @ 500 deg F; 316L-SS Tube Side rated 75 PSI/FV @ 500 deg F. (104) Tubes with 5/8" OD x ~ 24' long. Shell diameter - 10" x 25' L. Mfg: Southern Heat Exchanger, NB #2268.