Source Outdoor Race 3L Hydration System / 15L Cargo Pack Lightweight, mid-volume hydration pack with expandable cargo volume up to 15 liters; 3-liter Widepac hydration reservoir Large main cargo compartment with expansion zipper; external essentials compartment; fast access hip pockets for more storage Padded shoulder straps; adjustable sternum belt; removable waist belt; 70D ripstop nylon construction Taste-free reservoir with maintenance-free Glass Like liner prevents bio-film build-up Rounded Helix bite valve delivers a full flow with just a soft bite; built-in safety shutoff mechanism