SodaStream Mechanism

I discovered that my Singapore SodaStream did not accept Australian bottles. Rather than an adapter I rebuilt the little gizmo which accepts the bottle. Aussie bottles use a M22x2 thread.
Probably best to print at 100% fill to give it a fighting chance at being air tight and not blowing up. Only a very small passage actually receives any pressure and beefing it up would not effect the fit of the part.
You could also use this as a base for creating other adapted filling solutions.