Vessels for carrying water are known from ancient times. In the armies of all countries and peoples, at different times, soldiers used wineskins (leather bags), and bull bubbles, and dried scraped pumpkins, and barrels, and pitchers, and water-bearing baklags, and tanks, and manners, and even ... teapots ( remember the Red Army soldier Sukhov from the "White Sun of the Desert")). But as a result, they stopped at the usual jar, which is used by army men and civilians-fishermen, hunters, and travelers.The advantages of a modern flask are obvious: wear-resistant, practical, convenient to carry on yourself, reliably and nadol It still maintains the potable water availability.
Also at zero in ZA, a very good version of the experimental jar that is part of the "Belozor" research kit ran in. The housing of the flask, with a capacity of 0.75 liters, is made of aluminum and has double walls between which there is a heater. The kit also includes a 0.2 liter mug, which is essentially a jar and a mug, very comfortable, made of aluminum.
Evil tongues say that it was the "Belozor" that the Chinese themselves lied to. Indeed, the PLA in the standard arrow gear has similar bowl flasks, but they are made of stainless steel, and therefore very heavy. Although products made of stainless steel seem brutal and aesthetic, they can not be taken away from them.