Mizuno

These two drivers benefit from large, lightweight carbon-fibre sections on the top and on the sole to produce different ball flights and to resolve various performance challenges. The way this works is that the lightweight carbon-fibre panels reposition each driver’s centre of gravity (CG). The ST-Z features sections in the sole’s heel and toe that lower the CG to produce a neutral ball flight with lower spin and maximum forgiveness on off-centre hits. The ST-X boasts a larger panel stretching across the toe and centre of the sole. This leaves a heavier, all-titanium section concentrated in the heel. The heel bias is bolstered by an 11-gram fixed weight screw that helps slicers return the clubface to square at impact. (A lightweight option on the ST-X includes a sub-40-gram shaft.) A forged super-alloy titanium face insert features a new variable-thickness pattern for better flexing on off-centre strikes, and the wave shape in the sole extends the hottest area to include impacts lower on the face.

LOFTS 9.5, 10.5 (st-z); 10.5, 12 (st-x); adjustable