CURVIMETER

   Measure maps the fast accurate way with the Scalex Map Wheel.
    The perfect tool specifically for taking scaled measurements from maps.
    19 built-in scales to choose from.
    Measures in miles kilometres and nautical miles.
    The measurement is displayed instantly with an accuracy of ±0.25%.
    You can also create and store your own scale factors.
    Features counter and adder buttons to let you count stops made or add fixed destination lengths as you measure.
    The easy-to-read LCD shows length count and scale factor simultaneously.
    Powered by 2x AAA batteries (included).
    Auto shut-off to conserve battery life.