Souveran - A world-famous classic. The transparent casing is subject to an elaborate process. The material of the casing consists of high-grade resin and it takes a month until it is finished, whereupon the tailor-made plating is curved and cut into a contour using a natural diamond. The one piece cap and filling knob rings, each with a glossy and satin finish, give this fountain pen an extraordinary look. The green transparent components allow a view of the piston mechanism and also the ink level. The fountain pen with M800 piston filling mechanism consists of a 18-carat bi-color gold nib with rhodium trim and is available with the sizes EF, F , M and B.