'70s modernization of a design from the year 1910. Battle-proven, these still see use.
The ALICE pattern canteen pouch is over 100 years old in principle: it's based on the M-1910 canteen pouch. The biggest differences are that the exterior is nylon instead of canvas, and the attachment system is no longer the steel wire contraption, but proper US keepers, which are usually included.
The inside has a fuzzy faux fur lining and the bottom has a drain grommet. In hot climates the pouch is drenched in water, the lining soaks up quite a bit of it. As the water vaporizes, it keeps the contents cool for a longer time. Being an open-top design, the top and cap of the canteen remain outside while two snap-fastened flaps ensure the canteen doesn't fall out.
Apart from the obvious US canteens, these will take many similar bottles, including the Finnish 1 liter model.
The ALICE system has been replaced by MOLLE some time ago already, but you still see these in use by the US and other armed forces on backpacks and combat belts. A canteen is still a valid way to carry more water than a hydration bladder allows, and in case you need to clean a wound or just some shit from the eye, a canteen is more hygienic than a saliva-infested drinking tube.
These pouches are well used, some may have seen several wars. They might look a bit rough, but still, do the job they are meant to. The metal keepers might be original US stuff or reproductions.
Will G.
Nicolai R.
Xander E.