The idea of training is to start with the lightest balls and then gradually increase the weight. Just like you do during a workout. Geisha balls allow you to have 5 training stages. After that, experienced users can train with the individual balls without the strap. So when you feel yourself sufficiently trained with a weight, you don't have to go to a store and buy other heavier balls. You just need to remove the heaviest balls from the Geisha balls set.