Platypus Big Zip Ii - 3L Hydration Pack.
The Platypus Big Zip II is a durable hydration reservoir made from taste-free triple laminate material. Big Zip reservoirs will fit into any compatible rucksack (most brands) and the tube can be attached near your mouth with the included lapel clip for easy access.
The HyperFlow bite valve allows hands free drinking so you can hydrate yourself on the go. Attached between the Hose and the bite valve is a shut off valve that is angled at 90º which prevents drips and provides a more ergonomic angle to drink from.
The advantage of this particular Platypus is the big zip that opens into a very large hole so you can refill much more quickly from rivers etc.