Mizuno ST-Z Driver

From the manufacturer

Highly resilient Forged SAT2041 Beta Ti Face:  As a high strength Beta Ti, SAT2041 maintains its characteristics and resists micro fractures for longer than the commonly used 6-4 Ti.
New Multi-thickness CORTECH Face: Refined to maximize the return from Mizuno’s Beta Ti face. Ball speeds most noticeably improved low on the clubface
Quick Switch Adjustability: 4 degrees of loft adjustability to fine-tune look and trajectory
Optimized Wave Sole Plate: Delivers an additional contribution to ball speed – low from the clubface
Z Axis design for straight-line flight: Balanced use of carbon composite on the sole and deep central sole weight are biased towards a straight-line flight and low spin efficiency