1st Endurance EFS Drink Mix refuels muscles faster than before thanks to the latest in amino acid technology. The taste is not overpowering or chalky making it easy to consume during high intensity exercise while not upsetting your stomach. The drink mix is available in four great flavors that include grape, lemon-lime, orange and fruit punch. First Endurance is proud to say that their EFS Drink Mix offers the highest electrolyte content available out of any competing drink mix. Train and race with confidence knowing you no longer have to worry about dehydration or cramping.