ALL Keystone Sets are created to maximize your training based on your physical weight. The balls are calibrated to your approximate body weight. Hence, the Standard Set (offered below) is 10%+20%+30% of body weight for people weighing between 130-175 lbs. However, as you increase your training capabilities, you can then move up to the Super Set and eventually, the Great Sets, each of which increases the ball weight to a greater percentage of body weight. See our Training section for more information on this topic.