Swing weights are the yardstick for weight balance. The swing weight is divided into 5 levels, from the lightest head side to A, B, C, D, E, and even the same A is divided into 10 levels, from A0 to A9. Even if the total weight of the club is the same, the closer the club is to the A0, the lighter the head feels, and the closer the club is to the E9, the heavier the head feels.