the co2 bulbs used for soda streams are the same ones for pin valve kegs , so if you have flat beer and you got a keg you could empty (if you was gonna drink em then and there) 5 or 6 pints etc into a keg and use a bulb or 2 and it will carb up your beer
just thinking iv got 20 pints of flat beer that tastes ok but i like a bit of fiz , if could pint by pint get it a quick fiz it would be nice and easy unless im messing something .
on a side note a mate of mine was on the first or one of the first soda stream box's :)
his dad designed it