Callaway big bertha alpha 816 double black diamond driverextreme distance for better players featuring a deeper face next gen rbullmoto face and dual distance chambers with the gravity core for optimized ball speed and shot shapingextreme distance from dual distance chambers if yoursquore looking for a neutral or draw ball flight to work the ball with more control pick the left or right chamber then set the gravity core up or down depending on where you hit the ball for maximum ba