In brief, the Callaway Ai Smoke Max Driver is the standard version of the driver designed for the majority of players. The Callaway Ai Smoke Max D Driver is the draw biase version aimed to encourage draw spin and minimise slice. The Callaway Ai Smoke Max Fast Driver is a lightweight version aimed at getting the ball airborn more easily for Senior golfers or players with slower swing speeeds. And lastly the Callaway Ai Smoke Triple Diamond is a better players club, with reduced spin and a slight fade bias for strong golfers looking to shape their shots.