This is a NCSTAR Pouch known as the Hydration Bottle Carrier, model CVWBC2948U.
Here's a great way to take along a water supply on your next day hike or other outdoor adventure. The Water Bottle Carrier from NcSTAR holds bottles up to 32 ounce and features three rows of MOLLE webbing all the way around. A zippered front utility pocket holds your keys" smart phone" digital camera or wallet. The adjustable shoulder strap has swiveling plastic hooks" and two PAL straps allow you to attach the bottle carrier to other MOLLE compatible systems.
Features:
MOLLE Hydration Bottle Carrier
Zippered top lid and a pass through hatch for drinking tubes
Drain Grommet located on the bottom
Accessory pocket
Bottle compartment size 10 x 4 diameter