Make sure you have the convenient hydration of the UltrAspire Alpha 2. 0 Hydration Vest the next time you're at the midpoint of your latest 50k. This vest features comfortable, breathable micro-fiber fabric, a two-liter hydration bladder, a plethora of pockets for your energy food, electrolytes, and salt tabs, and back quick stash pockets that you can access without taking the vest off.