Callaway Mavrik,Epic,Fusion,BB Driver SHAFT between Reg&Stiff Bubba uses BiMatrx
COMPATIBLE WITH; MAVRIK, Rogue, SUB ZERO EPIC EPIC FLASH FUSION BIG BERTHA 816/815/814, XR, XR16, XR1, BIG BERTHA ALPHA 816, X2 HOT, X2 HOT PRO, OPTIFORCE 440,460 DRIVERS. BiMatrx is currently what Bubba hits in his driver.