ST-Z 230 DRIVER PRODUCT FEATURES CORTECH CHAMBER The missing piece: Mizuno's CORTECH Chamber encases a 3 gram stainless steel weight with elastomeric TPU - taking stress from the clubface and creating an additional source of energy. FORGED SAT 2041 BETA TI FACE More resilient than commonly used 6-4 Ti, now even engineered even thinner, with stress unloaded to the CORTECH Chamber. UNIFIED SOLE COMPOSITE Carbon sole plate now a single piece to allow the forward weight press of Mizuno's CORTECH Cha