The 3 Liter Hydration Bladder. Our backpacks are ready to accommodate top-of-the-line hydration systems. You’ll find that they have dedicated bladder pockets, louvered tube portals, and tube clips on the harnesses. We've found what we think is the ultimate hydration bladder system. Made by Source®, our premium bladders use patented anti-bacterial technology, and Glass-like™ liner, so that you get a product that gives great tasting drinks and long life. Plus, we've added our own specifications to make this into the hydration system that best does the jobs that we know our customers will be doing. Special standard features include dual fill options (wide-mouth or screw cap), weave covered insulated drink tube, and a dirt shield for the drink valve.