Designed as a lightweight and stable alternative to floppy running fanny packs, the CamelBak FlashFlo 45 oz Lumbar Pack is a reliable solution for trail runners and fast day hikers who can't afford to go thirsty. With a 45-oz. (1.4-liter) capacity, the CamelBak FlashFlo rivals the hydration potential of most water bottle fanny packs without the threat of catapulting sloshing bottles on rugged or twisting terrain. The wide mouth Omega reservoir opening is accessible from outside the pack, making it easy to refill without removing the hydration pouch from the pack. There's also a secure pocket sized right for your MP3 or CD player and a pair of compact headphones. An additional smaller external zippered pocket stores your SUV keys, hotel card, energy bars and other small essentials. Compact, jiggle-free design with a 1.4-liter capacity and room for a CD or MP3 music player.