Once ball speed is maximized with launch angle and spin rates optimized - the final route to elevated driving performance on the course is greater consistency. Step up to the Next Generation of Mizuno's ST Series - the new ST-Z 220 and ST-X 220. Engineered to produce your most efficient drives and highest ball speeds.more often. ST-X HYBRIDS DRAW BIAS - HIGH LAUNCH A confidence-inspiring hybrid - engineered to produce a higher, draw biased flight. The ST-X hybrids are suited for moderate swing s