These enamel water canteen's were introduced into service after WW1 until the start of WW2. They were unpopular as they did not carry enough water and were dropped from service making them almost rare. They normally come with a cup/canteen but it is hard to find a complete one today.
This example is Green in colour and does not have the cup/canteen. It is contained in a normal issue water bottle carrier and that is how I received it.