With Stealth™, there's always room for water - even in tight spaces or cramped environments. Includes our Quick Link Exit Port and QL HydroLock Bite Valve Adapter 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 Mil Spec Antidote Reservoir with external fill, 500D Cordura® fabric