For extended trips which require plenty of water why not choose the biggest version of the Antidote. It holds 100oz or 3 Litres of water with great, well thought out design features. It has a good, low profile with a baffle to help stop water swishing about too much as you move and a Quarter Turn easy open valve for filling which is one of the widest around so you can get your whole hand in for easy cleaning. Hidden Drier Arms enable you to flip the pack open to get 360 degree air ventilation for hang drying after you have finished your trip. You can customise your pack by attaching an Insulated Drink Tube, Flow Meter or a Fresh Water Reservoir.