Callaway Big Bertha Alpha Driver Gravity Control Adjustability: For the first time ever Gravity Core: Only the Gravity Core from Callaway allows to adjust freely Adjustable Weights Advanced Adjustable Hosel: Increase or decrease loft in 1Degree increments (up to +2Degree or down -1Degree) with the adjustable hosel Forged Composite: High Strength, Lightweight crown saves 20g of weight, allowing Big Bertha to have Gravity Controlling Adjustability