At the end of 1964, Pelikano underwent a fundamental revision (from model 1 to model 2). In 1965, all previous piston filler models (400NN, 140, and 120) were discontinued. With this, fountain pens with "classical design (open nib plus green and black combination)" disappeared from the catalogs, and in turn Pelikan started to introduce M series with rolled gold cap (e.g. M60, M30). M series was more a development of the Pelikano (model 2) than a development based on 400NN or 140. In 1966, Pelikan started to introduce less expensive MK series with plastic cap and steel nib (e.g. MK10, MK20, MK30). In line with the revision of Pelikano in 1968, M/MK series was revised between 1969 and 1970.