Selters is a German brand of natural mineral water sourced from wells in the area of Selters in Hesse, at the Taunus mountains. The water has been known since the Bronze Age and famous as a natural soda water because of its high concentration of sodium bicarbonate, "soda". The Selters water also contains raised levels of calcium, chloride, magnesium, sulfate and potassium ions. The water is naturally carbonated, over 250 mg/L, but sold in both sparkling and still versions.
The name and the water of Selters are the prototype of seltzer, a generic term for soda water in the United States.