A fin for a heat exchanger includes a member and a first row formed in the member. The first row having a plurality of valley sections alternating with a plurality of crest sections. A plurality of walls is interposed between and integrally joins the plurality of valley sections and the plurality of crest sections. At least one of the plurality of walls of the first row is angled with respect to a lateral axis of the member. A second row is formed in the member, the second row having a plurality of valley sections alternating with a plurality of crest sections and a plurality of walls interposed between and integrally joining the plurality of valley sections to the plurality of crest sections.