Co2 - 60l sodastream exchange cylinder, turns water to sparkling water in seconds, co2 cylinder contains pressurized pure beverage grade carbon dioxide & is made of lightweight aluminum, control the sparkle in their drink by adding as much or as little co2 as they prefer, exchange & spare co2 cylinders create customer convenience, when cylinder is used up, customers simply exchange it for a full one, paying only the cost of the refill, empties are returned by the retailer to sodasstream to be cleaned, inspected & refilled, spare cylinders are also available for customers who want to keep extra co2 on hand.