In 1934 Montblanc introduced the standard piston filling mechanism and reviewed its line of pens. The numbering system was organized to distinguish three line of piston fillers where the first digit ( 1/2/3) refers to the price range 1: Meisterstuck line -  2: Medium range - 3: Economic line), the second digit refers to the filling system (3 is piston) and the last digit indicates the size of the nib.

The sizes 234 1/2 and 334 1/2 were dubbed "standard" as they represented the size which would fit most hands; these were produced in black and in a variety of marbled celluloid colors which are nowadays extremely rare and desirable.

This Montblanc 234 1/2 in green marbled celluloid is new old stock. The pen has never been inked and is fitted with a very pleasant Montblanc 4 1/2 nib which is smooth and nicely flexible.