This is a Montblanc Meisterstück 146 fountain pen from the 1950s. A masterpiece of vintage fountain pens. The ink filling system is a piston filler, a monster of its kind, featuring the telescopic design that Montblanc was proud of during this era. The nib is a two-channel ebonite, the ring on the barrel end is rounded, and the cap has an air hole. The "146" number is engraved on the barrel end, not the cap ring. And the white star has aged to an amber color. It has all the characteristics typical of Montblanc from this period. Furthermore, the nib is a rare oblique broad (OBB) size. The OBB marking is on the barrel end. However, there is a flaw. The telescopic piston functions, and it can be filled with ink, but some ink leaks from the area between the barrel end and the body during filling. Wiping it off allows for normal use afterward, but it's likely that the internal packing is weakening. You can either consider the inconvenience during filling as part of the "flavor" of a vintage fountain pen and use it as is, or you can have it repaired, depending on your preference.