The Vertical 4 Hydration Pack has a 100% bounce-free design with the award winning and patented NDM™ harness system. The harness is ergonomically designed and completely adjustable with soft mesh, highly ventilated shoulder and chest straps that work with your movements allowing great stability while providing full freedom of movement. The pack has a 4-litre volume that is spread across a large main compartment, and several other compartments which help you organise all your gear. The rucksack also comes with the USWE 2L Hydrapak Elite™ hydration bladder. The bladder is easy to refill and to clean with a Slide-Seal™ top and completely reversible design.