Used 194 Sq. Ft. Bos-Hatten Inc. Horizontal Shell & Tube Heat Exchanger. Carbon Steel shell rated 75 psi @ 200 F, Stainless Steel "U" tubes rated 125 psi @ 200 F. Serial # 11944-A, National Board # 710, Built 1971. Previous Use: Nitric Acid - Product Acid Cooler