Simple and Lightweight,
I purchased this primarily for biking, it's great and has a perfect size pocket for a phone or wallet. You can hardly tell it's on when you get going. I also took this to Coachella this past year. Having it inside festival grounds when water costs several dollars a bottle was totally worth the price of the bag alone. 2 Liters is plenty water for what I use it for. I love it! throw some ice in it and you're good to go.