Souverän M300 was introduced in 1998, and was the smallest piston filler fountain pen on the market at the time⁽¹⁾. It is said that the initial nib of M300, along with M1000, was one of the softer nibs in the Souverän series (万年筆評価の部屋)⁽²⁾. Since it could write even with low pressure, the nib would fit its small and light body. M300's small size and portability made it suitable for simple notes and organizer entries, but it was too small for long hours of work, such as writing letters or diaries. With advances in technology, paper organizers were no longer necessary for many people, and the popularity and demand for M300 declined (Pelikan’s Perch). M300 was discontinued in 2020 (Pelikan’s Perch). At this time, M300 is the only Souverän series that has been discontinued.

Note;⁽¹⁾All of the competitors of a similar size were a converter filler (Pelikan Schreibgeräte).
⁽²⁾The characteristics of the nibs changed in the mid-2000s (Fountain Pen Network).