Gerolsteiner Brunnen GmbH & Co. KG (Gerolsteiner) is a leading German mineral water firm with its seat in Gerolstein in the Eifel mountains. It is well known for its Gerolsteiner Sprudel brand, a bottled, naturally carbonated mineral water. This  water, in addition to hydrogen and oxygen (H₂O) and carbon (in the carbon dioxide (CO₂) carbonation), contains at least the following chemical elements in amounts of 100 or more micrograms per liter:  bromine, calcium, chlorine, fluorine, lithium, magnesium, manganese, nitrogen, potassium, silicon, sodium, strontium, and sulfur. The strontium is naturally occurring, not the radioactive strontium-90. Gerolsteiner was also the chief sponsor of a cycling team, Team Gerolsteiner.