A nickel plated cased, glass bottle with stopper.
The case is both light but strong and thanks to a removable corrugated card liner, the bottle is a tight fit. The inside of the top of the case has a cork pad to further protect the glass and prevent it from moving within the case. The top has a simple twist action for locking it with the base having 3 lugs that fit to corresponding slots to the rim of the lid. This bottle could have been used to hold any number of liquids from spirits to milk or medicines. Likewise, it could have been used on a number of occasions from picnics, field and other sports to military use.
There are no markings or evidence of a maker and it is likely a number of manufacturers produced similar cased flasks. Early 20th Century.