Source Outdoor Brisk Low Profile Hydration Backpack Pack with 2 Liter Taste Free Widepac Bladder - Outdoor Sports Gear for Hiking, Cycling, Running Low-profile hydration pack with selection of 2-liter and 3-liter Widepac hydration bladder; ideal for trail running, hiking, and more Comfortable padded shoulder straps; small compartment for essentials; external storage via adjustable bungee cord Durable 70D ripstop nylon construction; separate insulated hydration compartment 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