Mighty Therm, Complete Heat Exchanger Assembly (double pass, 18 tube), 4050I/3600E. LAARS Code Compliant ASME Heat Exchangers with Headers Built in accordance w/the requirements of the ASME Boiler and Pressure Vessel Code. Individually serialized w/H-4 data reports on file as required by section HG-520.2 and HG-531.