The piece is a Montblanc SlimLine (SL) cartridge fountain pen, built between 1979 and 1982. It has a brass core with plastic surface, gilded trim and a gilded steel nib; the then shop price was about 49 DM. The SlimLine series was settled in the lower price segment, intended for school pupils and students, and lay below the Noblesse and the Meisterstück ranges. A rough model determination based on clear photos is mostly possible; with rare pieces a personal assessment is necessary.