The four most common map scales an outdoor adventurer will encounter in the Continental United States.
These rulers can be used to measure or plot latitude/longitude coordinates, UTM/MGRS/USNG coordinates, and to measure distances in either meters or miles.
On the front side, the rulers have minutes and seconds on one edge and decimal minutes on the other edge, allowing you to use either notation. On the back side, the rulers have distance in meters on one edge, and distance in either miles on the other edge.
Latitude is measured directly with the rulers. But, since a degree of longitude covers a shorter distance as you move towards the poles, the rulers are used on a diagonal to measure longitude. See the usage diagrams for more information.
The rules are packaged in a handy clear vinyl storage pouch, and includes instructions for use.