Mizuno ST-X 220 Driver (Right-Handed)Mizuno ST X 220 Driver A confidence inspiring, draw biased driver with heel focused weight location. The ST X will appeal to players seeking a higher, right to left ball flight. With higher spin rates than its ST Z counterpart, the ST X 220 will suit moderate swing speeds, needing help producing a more extended ball flight. A new 20 gram heel biased back weight creates a deeper center of gravity for more efficient, longer drives more often. Also