In general, in practice, taking into account the vastness and the number of climatic zones of the Russian Federation, the best material for a single army flask is of course aluminum. Light and slightly inert metal. Optimum volume: 750ml-1l.
Of course, in the hot climate of Afghanistan in the CA, jars of transparent plastic were very popular.
They are lighter in weight, and do not heat up in the sun like metal. I will return to our sheep. So, glass jars are known since the end of the First World War. They entered the army of Germany and the Russian army (RA) after the metal resources were exhausted and it was necessary to buy it abroad or to economize heavily on the leftovers. It was these flasks that were used at the beginning of the formation of the Red Army and the entire civil war, and white and red.
In 1932 they again began to produce glass jars. This is an important nuance-practically everywhere sources indicate that the glass jars returned to the Red Army only in 1941, due to the lack of metal.
As we see, this statement is erroneous, in the time of peace, flasks of glass were also produced.
Here are the documents.
The use of any mineral additives for glass was allowed. And as a result, the glass jars turned out to be of different colors. Yellow, green, brown, colorless .