Contoured back panel with Mil Spec Antidote® Lumbar Reservoir makes this our most comfortable pack for 1-2 day excursions. RESERVOIR FEATURES: 100 oz Mil Spec Antidote® Lumbar Reservoir repositions water weight low and on your hips for a lower and more stable center of gravity with easy-to-fill and clean wide-mouth opening, rugged and durable material, leak-proof ¼-turn cap, insulated PureFlow™ tube, patented Big Bite™ Valve, Quick Link™ Exit Port and Drink Port, QL HydroLock™ one-handed flow control. KEY PACK FEATURES: Sleek, low-profile Composite MOLLE panel provides secure attachment for pouches and gear; Internal composite MOLLE panel allows custom configuration of essential gear/pouches; Composite MOLLE on harness for front-facing pouch attach; Full clamshell opening for easy access to main compartment; Lower access zipper allows you to quickly stash or grab an item from the main compartment; Multiple drink tube exit ports for routing tube over the shoulder or under the arm; Fully adjustable waist-belt stows easily when not in use