These soda bottles are still commonly used in India. The 'Codd-neck bottle' is a British design, which was specially designed for carbonated drinks. The bottles are filled upside down, so the pressure of the gas pushes the marble up the washer, sealing in the carbonation. To open the bottle, you simply push down the marble and it slides in the compartment in the neck. This way it does not block the neck when drinking. They can be used over and over again. In India you still see vending carts, selling these bottles with cool drinks.