Used 1002 Sq. Ft. horizontal steel Shell & Tube Heat Exchanger. CS Shell rated 150 PSI @ 400 deg F, Bimetal Tubes rated 150 PSI @ 400 deg F. (319) tubes 3/4" OD X 16'. Tube Material: Type SA-174 inside, SB-111 Admiraly Brass outside. Shell: 1 Pass; Tubes: 2 Pass. Mfr: TMF, Model 21-0002-16. S/N: 3429B, National Board# 178. Type AES.