Product Information The Spry 2.5 Hydration Pack is a minimalist vest that can be used for everything from a 10k to a 100 miler. The Spry 2.5 is equipped with Max 02 Sternum, trash pockets, shock cord for greater versatility and a larger quick stash in the back for more carrying capacity, 1Lt bladder compatible. One size fits most. Ultrarunning Magazine top pick. FEATURES - Quiet, bounce-free, lightweight, soft and non-abrasive against skin and clothing; its breathable but strong, large-holed mesh pulls moisture away from the body to keep skin dry and cool FLUID CAPACITY - Compatible with 2 UltraFlask 550 mL bottles (not included) and a 1 L reservoir (not included)MAX 02 STERNUM - For unrestricted breathing while maintaining a stable pack. Uses shock cord with good stretch for unrestricted breathing but also good rebound on the stretch for a stable ride CARRY EVERYTHING YOU NEED - Rapid access pocket and let the consumer decide what goes in, such as gels, foods, pills, electrolytes, keys, a cell phone or any other small personal device, a credit card or money, and even light clothingRECOMMENDED USE - Flexible for light and fast ultra-races with frequent refueling stops; ideal for runners who prefer to carry their own supplies during a marathon or a half marathon