EFS (Electrolyte Fuel System) energy drink combines the latest clinical research and technology with input from some of the best endurance athletes in the world. The result: a great-tasting energy drink that provides ALL the ingredients you need to maximize endurance. Clinical research shows endurance athletes require much higher levels of electrolytes than most sports drinks provide in order to prevent cramping and dehydration. Each serving of EFS provides all five electrolytes in the levels endurance athletes need to stay hydrated and maximize endurance. So you don't have to carry extra electrolyte pills or bother adding anything to your energy drink anymore.