With more professional tour wins than any other graphite iron shaft in history, SteelFiber iron shafts are the preferred option by the worlds best. SteelFiber Private Reserve shafts take that excellence to the next level by providing Aerotechs unique SteelFiber technology in a range of shafts that feature ultra-tight tolerances for the player seeking the best. SteelFiber Technology Promotes: Thinner wall thickness for improved feel, Superior hoop strength for increased stability and energy transfer, and Perimeter weighting, shifting the shafts CG outward?increasing the shafts MOI