ITT Standard U-tube heat exchangers with copper tubes. 2, 4 and 6 pass models covering areas as large as 1900 square feet. Shell Diameters from 4″ to 29″ OD. 3/4″ OD Tubes. ASME Code constructed. Available as B300S for Steam applications or B300W for Water applications. SX2000U only available with 3/8″ OD tubes.