A cooling unit, a heating-cooling operation including a cooling unit, a rod or wire manufacturing system, a method for manufacturing a rod or wire, a method for heat treating of a rod or wire, a method for treating metal, a steel rod or steel wire, and a treated metal having an improved tensile strength are disclosed. The cooling unit includes at least one adaptable quenching zone and at least one adaptable soaking zone. The at least one adaptable quenching zone is capable of quenching to a soaking temperature. The at least one adaptable soaking zone is capable of maintaining substantially the soak temperature.