There is disclosed a heat exchanger for transferring heat between at least two fluids and a method for forming the heat exchanger. The heat exchanger preferably includes one or more end tanks, one or more inlets and outlets, one or more tubes, one or more fins, and one or more improved baffle combinations including at least one single piece double baffle. The improved single piece double baffles act as part of a baffle system, with advantages over multiple-piece only double baffle systems due to being assembled in one piece.