Callaway big bertha fusion driverldquobig bertha fusionrsquos innovative construction which combines a titanium exocage with a triaxial carbon crown and sole wouldnrsquot be possible without the nearly 20 years wersquove spent researching and developing carbon fibertechnologyrdquo dr alan hocknell senior vice president rampdbig bertha fusion pushes the boundaries of forgiveness like no callaway club ever hasthe key benefit more forgiveness means straighter flight on mis hit