When any fluid passes over a surface, a stagnant fluid layer or film builds up adjacent to the surface which it is in contact. The greater the contact area and/or longer contact length the greater the stagnant layer becomes. In similar fashion, air passing over a plain or smooth fin surface forms a stagnant air film that reduces thermal conduction and lowers the rate of heat transfer from fin to the atmosphere. The High Performance Fin’s interrupted surface through its radial openings, prevents this stagnant film of air from reaching its maximum thickness thus increasing the outside film transfer coefficient. Most importantly, it does not increase the turbulence of the air passing over the fins and the result is an increase in overall heat transfer rate without an increase in static pressure or fan horsepower.