This low profile pack has enough room for the essentials and keeps you maneuverable.More than just a reservoir, the Mil Spec Antidote® reservoir redefines the ultimate delivery system for an operators water supply and provides maximum adaptability for changing missions or combat environments. Includes our Quick Link Exit Port and QL HydroLock Bite Valve Adapter: tube clicks off for faster refilling with auto shut-off; new fillport: industrys largest opening with air-light ¼ turn open/close for quick, secure seal that cant be over-tightened; lighter-weight, lower-profile design. External fill accessallows for a quick refill without removing pack; Side-release shoulder straps for rapid removal; Multiple drink tube exit portsfor routing drink tube over the shoulder or under an arm; Top and bottom external pockets hold small essentials; Lightweight, durable Rip-Stop Cordura® Fabric. If we built it, we'll Bak it with our lifetime guarantee.