CamelBak. In this section you will find the full range of Camelbak Hydration Systems for military or general use from cycling to long haul trekking. These systems are used by filling the bladder reservoir with water and placed on your back like a rucksack you may then drink the water through the tube allowing you hands to be free and having no need to stop to drink. These packs will hold up to 3 litres of water. Most colours are available including British DPM.