The Sinus ashtray is perhaps the most recognizable object designed by Walter Zeischegg. It is made by Helit out of melamine in just about every color of the rainbow. This ashtray has frequently been employed as a promotional or advertising item. In production for a long time, the Sinus has come in different style boxes and with many different imprints stamped on the underside. It is sometimes called the “wave-stacking ashtray.” The Sinus ashtray is part of the permanent collection of the Museum of Modern Art in New York.