The BNZ design consists of an outer housing shell and a tube / fin bundle known as a “stack”, which fits inside the shell. Hydraulic fluid to be cooled is circulated through the housing shell and passes across the cooling fins, which transfers the heat to the cooling tubes in the stack. Cooling fluid, typically water or water-glycol, flows through the cooling tubes running through the stack to carry the absorbed heat away. This rugged design offers high heat removal in a compact package. A large variety of cooling capacity sizes, port options and material choices are available to tailor the optimum cooler to meet specific application needs.