An apparatus for transferring heat from an electrical module includes: (a) a thermally conductive base member having a plurality of edges establishing a polygonal perimeter and having a first side for presentation toward the electrical module; and (b) a heat transferring structure integrally formed with the base member and extending from a second side of the base member opposite from the first side. The heat transferring structure occupies less than all of the second side and establishes a margin substantially about the perimeter.