Souverän - A world-famous classic. The deep black casing is subject to an elaborate process. The material of the casing provides high-grade resin and it takes month until it is finished, whereupon the tailor-made plating is curved and cut into a contour using a natural diamond. The characteristic double rings are then integrated into the cap and barrel with the utmost precision. The writing instrument is then polished until it reaches a brillant luster. The fountain pen M1000 with piston filling mechanism provides a 18-carat bi-color gold nib with rhodium trim.