Reels or spools for carrying wires or the likes, where the flanges of these reels or spools have corrugations with undercuts selectively formed thereon, are provided. These undercuts may aid in the molding process, such as injection molding or compression molding with substantially rigid molds, among other things. The reels or spools may also have supports dispersed between the corrugations to provide additional structural integrity to the flange. These supports can be mid-plane supports between the corrugations and may be positioned closer to the inside surface or to the outside surface of the flange, and the supports may form an angle with the corrugations.