With the Platypus® Big ZipTM LP Hydration Bladder, it's never been easier to keep hydrated on the trail. This reservoir features a low-profile design that easily slips into most backpacks. A durable exterior film is laminated to a taste-free food-grade liner that maintains the fresh taste of water. HyperFlowTM Bite Valve has a high flow rate for fast, hands-free hydration. Connects directly to a GravityWorksTM water filter (not included) for optimal efficiency.