Nathan Synergy Bladder Dual Chamber Replacement Hydration Bladder - 3 LNathan Synergy Bladder Dual Chamber Replacement Hydration Bladder 3 L The Nathan Synergy Dual Chamber Bladder water pouch is a very ingenious and practical product for your long running or trail runs . It is a 3 liter water pouch coupled with an electrolyte pouch to allow you to make your own energy drink mixes according to your needs thanks to a concentration adjustment button. The valve has an ON OFF system which prevents the risk of leaks. Almost 3