Published April 12, 2019 17:53 What kind of metal are your cylinders made from? The body of our cylinders are aluminum, while the valves are brass. Related articles How do you get a CO2 refill when there are no exchange stores in the area? Does my CO2 cartridge have a lifespan, or expiration date I need to use it by? Does a customer get a deposit back for turning in their empty carbonator? What items are compatible with my sparkling water maker? Why does the carbonating bottle have an expiration date?