Abstract: A fin for a radiator for cooling a fluid, the fin being made from a thin sheet of heat-conductive metal. The fin has many stacked fin elements formed from a single sheet. While the typical radiator fin is formed in a serpentine shape with rounded edges, the fin of the present invention is formed so it has flat edges. This facilitates the attachment of the fin to the tubes and also increases the minimum spacing between the cross-elements of the fin so that the fin is less apt to plug up in addition to being stronger as a result of a large flat bonding area against the tubes.