Grohe Blue CO2 cylinders 425 g - Set of 4 piecesGrohe Blue CO2 cylinders 425 g Set of 4 pieces Code: 40422000 The Grohe Blue Kit containing 4 425 g CO2 cylinders is used with the Grohe Blue Home water purifier to carbonate the water filtered by the device. Do you love bubbles? This is a starter kit to be purchased together with the purifier to have a first supply of CO2 always available. Once the four bottles have been emptied, it will be possible to purchase the refill set, cod. 40687000, cheaper,