Mizuno ST-Z 230 Driver (Right-Handed)Mizuno ST Z 230 Driver The Mizuno ST Z 230 is a straight bias driver with excellent stability from off center hits. Similar in look and character to the previous ST Z. Boosted by the CORTECH Chamber to be faster from the face, spin less and deliver an incredible, solid sensation at impact. CORTECH Chamber The Missing Piece: Mizuno's CORTECH Chamber encases a dense stainless steel weight with elastomeric TPU, taking stress from the club face and