I saw an original in a Christies sale. It impressed me so much, I wanted one for myself.
I have seen no evidence of people carrying their own water. Many believe it was uncommon or dangerous to drink water but I find that hard to believe. Sailors on long journeys were able to collect rain water in sails for example and the wells around where I live in the Peak District, go back many centuries. Whatever you believe, the people must have drunk something and the country's population was sparse so there may well be times when a personal supply was needed.
There are two types of bunged vessels I've seen. One is shaped like a flattened light bulb and the other like a wine bottle with a snub neck. The former looks a little too like C18th powder flasks to me so I have opted for the latter. In the pictures you can see the original and one that we make here, before and after the beeswax is applied and then hardenned in the oven. The bungs are all different kinds; simple wood turnings that taper fit in the neck of the bottle.
The inside of the bottle can be beeswax or brewers pitch whichever you prefer. If you don't specify then you might receive whatever sort we arc currently making. When I say 'we' I mean we are a family business of husband and wife with my teenage daughter here in Yorkshire UK. We make everything by hand here in the workshop/cellar beneath the house.