Callaway Women's Great Big Bertha Driver Next Gen rmoto technology: to get every last yard out of your driver, you need more speed. That's why we put in our next Gen rmoto technology. It provides the Structure for a thinner Face, leading to high ball speeds on and off center-hits Light and stable head design: this is the best combination we've EVER had of an aerodynamic head shape and lightweight club design. It's the key to generating higher clubhead speed through aerodynamics and a wide range of weight classes for all Swings Forgiveness and Control from adjustable perimeter weighting: there's a 10g sliding weight on the perimeter of the clubhead. You have virtually unlimited draw and fade bias options, more additional draw bias than EVER before. With forgiveness Simple Adjustability: you can quickly slide the weight to any position you want on the Track. And the opti-fit hosel lets you choose from 8 different configurations to tune loft, lie, and Face angle