The Osprey Hydraulics Reservoir is a water reservoir for hands-free hydration. Bottles can be so cumbersome. When you're on the trail toss this in your pack easily thanks to the HydroStatic™ backerplate and drink from a tube. Leave your hands free and enjoy the hike, without getting dehydrated. BPA-free, phthalate-free and even lead-free, so you know you're not getting any weird stuff as you drink.