Mueller plate and frame heat exchanger, model AT184 ISB-10, serial number 396463, 4 each 4" Tri-Clover product connections, 4 each 4" Tri-Clover medium connections, 2 zones with regenerative block with 4 each 3" Tri-Clover connections, 72 each 24" wide x 72" tall wide gap plates, approximately 864 square feet of total surface area, 86 PSI maximum working pressure, 150 degrees Fahrenheit maximum working temperature, all stainless steel construction.