Early morning summit assaults and running rapids at high noon are what the CamelBak Arete 18 Hydration Pack craves. This sweet little pack has a ton of tricks up its sleeve. In its normal configuration, you've got storage for your jacket, snacks and sunblock, and a liter and a half of H2O. Three exterior pockets keep your essentials close at hand. The Arete™ also makes an excellent travel companion - it packs up tiny and weighs very little. But wait - there's more! Flip it inside-out and it becomes an insulated sleeve for its Crux™ Reservoir, perfect for stowing in your main pack.