Vaughn has created a niche market in the water heater industry, due to its product’s unequaled reputation for longevity, reliability, and innovation. Hydrastone is a ½” thick, seamless layer of specifically engineered cement lining that coats the entire surface of the inner tank protecting it from the corrosive effects of water. Click on Stoney to learn the unique manner in which Hydrastone works. But all you really need to know is that over the years, no other water heater has lasted longer, or proven to be more reliable than our Hydrastone lined tanks.