Outlander PRO is a superlight race hydration pack developed and designed around pro mountain bike athletes originally. The pack is stripped off to go minimum on weight and to maximize the ventilation at the front. It's like wearing nothing at all. This pack has revolutionized what athletes experience when training and racing with a backpack. Before, it was all a gamble between comfort, unnecessary weight, and hassle. Now, the choice is clear with a pack that allows 2L of hydration but fits like a glove that truly doesn't bounce around