Douglas Navigational Protractor 5" - D565 rechargeable Pair Tread with the compatible

Pair Tread with the compatible Garmin PowerSwitch digital switch box (sold separately) to enable on-screen control for your vehicle’s 12-volt electronics — light bars

GT20-TM transducer

Contact point set with wrench

This rugged

which allows you to toggle between the navigation display and backup display modes at the press of a button

Douglas Navigational Protractor 5" - D565 rechargeable Pair Tread with the compatibleCalled "navigational" primarily because it goes continuously from 0 to 360 as a compass rose does. Use for plotting lines of position in celestial navigation or for general plotting and vector problems on plain paper that does not have a compass rose. In England and Australia it is more commonly called a Douglas Protractor, where they are popular for general plotting.