Victorinox SwissCard Ruler
All SwissCards have a ruler on the back of the card. The ruler is is approximately 3 1/8" (80mm), which is the length of the card itself.
Tool Locations
This tool is found on the following Swiss Army models:
Other Rulers
On the smaller 2 1/4" (58 mm) Swiss Army knives such as the MiniChamp, the ruler is about 40 mm long (1 1/2"). It comes with a screwdriver blade at the end.
On larger Swiss Army knives, the fish scaler is also a ruler.
Many Leatherman tools also include a ruler on the body.