- 1). Read the last digit, or unit digit, of the Waterman's pen serial number. This digit tells you the size of the pen's nib.
- 2). Discover the type of pen described by the serial number by reading the next to last digit, or the tens place digit. For instance, number one describes a slip-fit eyedropper, a number five is used for a lever-filler pen and seven is used for screw-cap eyedropper pens.
- 3). Decipher the overlay and trim band configuration of the pen by reading the hundreds and thousands position, that is the third and fourth digit from the end of the serial number. For example, a solid gold cap top band will have a nine in the hundreds place, while a silver barrel overlay will have a two. Gold filled pens are the only ones that use the thousand place. They are coded with a zero.
- 4). Read the suffix at the end of the serial number to find additional information on the pen. For instance, a pocket model will have the suffix "V," while an overlay covering barrel will have the suffix "LEC."