The Alpha 3.0 vest is form-fitting and multi-functional. Whether you're out for a hike or a long trail run, this is the way to go. It has the capacity to hold 2 UltraFlask 550 bottles or a 2L reservoir, whichever you prefer. This pack also features a zipper pocket in the back to hold all the snacks you wish, as well as a new upgraded mesh material. This updated model of the original Alpha is more versatile than ever before.