Sodastream Carbonating Bottles (2 pack of 1 litre) are easy to use. Simply add water to fill line, carbonate with your SodaStream Sparkling Water Maker and then add flavour if you choose to. The Carbonating Bottles are compatible with Sparkling Water Makers; power, Source, Play, Spirit and Fizz. Do not use in dishwasher, freezer or with water over 50 degrees celcius.