Rand Mc Nally USGS Topographic Maps A number which often appears on the panel or in the margin of a map.
Take the last two digits of the last four numbers and invert them, e.g., 3680 1209R = 1990.
When was a lens announced, and is it still a current model?
Note that this is not always the same as when it first shipped - some lenses were 'previewed' a long time before they were officially released (the 200-400 being a notable example).
The first markings were added in 1957 and overlapped into 1958.
From 1957-1965 the code configuration on the slim lighters differed from the regular lighters (See Date Code Chart below). The appearance of the word "Zippo" in the bottom stamp provides another clue to dating.
We collect shipping information on purchases from the STORE which is used solely for shipping; we collect some information on various submissions which is used to verify that the submission is made by the person claiming to make it and for no other purpose.
Some older Canon lenses are stamped with a manufacturing code consisting of two letters and (typically) four numbers.
It's been suggested that the code starts in January 2008 with the number 38 and increments each month of the year.
This white sticker is located on the front side of some wireless product PCB's.
While the information for dating a Zippo is widely available, it isn't that handy to find it all in a single location.
Zippos had a flat bottom until 1946 when the bottoms were indented.
Starting in 1958 Zippo used date codes (there were prior date codes, but no one seems clear on exactly what they were).