The Montblanc 333 ½ dates from the 1930s and belongs to the 3 series, the firm's cheapest range at the time. These were solidly built everyday and school pens, produced in large numbers and for that reason still turning up regularly on the second-hand market. The number stamped on the end of the barrel is the model number, the half step marking a size variant within the series. The figure on the nib, 3 ½ here, gives the matching nib size. The letter combination OB stands for an obliquely ground broad nib, which produces a markedly varied line and is sought after today.
Its monetary value stays modest because of the large numbers made and lies well below that of the big models of the same period; it also depends heavily on the condition of the nib and the body. With an heirloom of this kind, using it is usually more rewarding than selling it, since the pens of the 3 series generally write very pleasantly. After a proper clean and, where necessary, a new piston seal, they make a good everyday pen.