Used 518 sq ft shell and tube head exchanger. Rated 75 PSI/FV @ 320 degrees F tube side and 75 PSI @ 400 degrees F shell side. Stainless steel tube side. Carbon steel shell side. Stainless steel heads. Horizontal design with saddles and expansion joint. 18" diameter shell. Model FTSMX-18-518. Perry Products. NB 4674. Built 1994. S/N: B4917.