You don't bring back a name like Big Bertha unless you've got something really new & exciting. Adjustable weights, adjustable lofts, adjustable face angle — it's all been done before. But an adjustable center of gravity? Now that fits the bill. And that's exactly what you'll find on the Callaway Big Bertha Alpha Driver. Like most adjustable drivers, the Alpha offers an adjustable hosel for for changing the loft and face angle, and movable weights for further launch adjustment, but adds a Gravity Core that allows you change the vertical center of gravity independently of everything else — giving you yet another way to custom-fit the driver to match your swing.