These cylinders follow the current market standard size and will fit most sparkling water and soda water machines on the market including the Aarke Carbonator itself and SodaStream, Levivo, Drinkmate, Phillips and all other Home Use Carbonators. You will receive 1 gas cylinder which should last approx 60 litres depending on how much carbonation you enjoy. We offer €20 discount when you purchase 4 canisters meaning you'll never run out of sparkling water again. Check out the bundle offer here Returning your empty cylinder You can drop your empty cylinder back to our store at The Kind, Unit 49, Blackrock Shopping Centre A94 XH79 and pick up a new one in store.  If that doesn't suit you can also drop off your empties to your local participating convenience store in Ireland. No need to print anything, it couldn't be easier. Simply go https://coll8.drop2shop.ie/ Select The Kind as the retailer Find your handiest convenience store Fill out the online form and that's it Please do add at least 4 canisters to one box as it will save on transport costs and is kinder to the environment :) Specifications Store your Aarke bottles in the refrigerator to chill before carbonating--cold water holds more CO2. Store your CO2 cylinders in a cool, dry environment. Avoid storing in direct sunlight or close to other heat sources.