Refill your flask! The First Endurance EFS Liquid Shot was developed after years of research and tons of feedback from athletes. EFS Liquid Shot provides the ingredients you need to maximize endurance and performance. The refill allows you to wash and re-use the handy and innovative 5 ounce flasks that come in the 6-pack offering. Each 5 ounces of EFS Liquid Shot delivers 400 high-quality calories, 1000mg of amino acids, and 1500mg of electrolytes so you don't need to bother taking extra electrolyte pills. It does not contain any gelling agents because First Endurance found gelling agents slowed absorption and digestion. Any flask will do, but the 5oz Liquid Shot flask has a re-sealable pop-top that allows you to take as little or as much as you want. It's also refillable and 100% recyclable.