Water backpacks (hydrators) – device allowing you constantly have up to 3 liters (depending of the model) of drinkable water which you can drink on the move, backpack removal is not required.
Now available different models of such backpacks with different types of fastening.
Typically, water backpacks are used by hunters, tourists and travelers.
User must calculate for what time of distance this water reserve is enough.
Most optimal choice are military module backpacks or its civilian versions.