These stainless steel carbonation caps are intended to convert 1L and 2L bottles to pressurised growlers. Fill up a 1L or 2L PET bottle with your beer. Put one of these on (purge the head space by squeezing if you want to) and then pressurise for transport. You can also use this cap to rapidly carbonate beer. Same process as for transport, just shake it up until it’s carbonated.
