Schott Zwiesel is known for its strong, light and beautiful glasses. They are manufactured of Tritan christal glass. This glass is developed by Zwiesel and is incredibly strong through which the fraction percentage is much lower than other christal glasses. These glasses are used a lot in the catering industry. By replacing the lead with titanium, they have much stronger glasses and they are also proof against the dishwasher. With 3 years of guarantee, Schott Zwiesel guarantees clean and glossy glass that does not change colour or becomes grubby in the dishwasher.