For slim cartridge pens of that period with a brushed metal barrel, the star in the cap top and the brand name engraved on the nib, three ranges come into question above all: the Turbo, the SlimLine and the Noblesse. All three were sold as slim everyday pens alongside the Meisterstück and differ in the shape of the cap, in the clip and in the transition to the section.
A firm identification is only possible with the pen in hand, or from sharp photographs of the cap top, the clip and the nib. Slim metal pens of those years look much alike from one maker to the next, so models by other brands are regularly taken for Montblancs.