This plotter contains mileage scales (in nautical miles) for all enroute IFR charts. Determines the scale of the chart to be used (usually indicated along the edge of the chart) and then select the corresponding mileage scale on the plotter. Available scales are as follows: 1": 5, 7.5, 10, 15, 20, 25, 30, 35, 40, 60, 80 and 100 nautical miles. Note that the nautical mile-kilometer conversion scale is included on the plotter for your connivance. When placed over a station, this plotter graphically shows actual standard (right hand) and nonstandard (left hand) turns for holding and entry pattern relative to your flight course. This APR plotter also may be used as a ruler using any of the mileage scales, but the 1", 10 miles scale is considered most convenient. Just remember that every 10 miles equals 0.1 inch.