This portable navigation system is designed for accurate navigating with any chart, chartkit or chartbook. the plotter is made of solid wood and an integrated adjustable parallel arm fitted with moveable compass rose. This permits the direct plotting of magnetic compass courses and firmly supports chart work whether in the cockpit, on deck, or below. Plot a course to a given point by locking the rule at a given bearing. By moving the rule so that the point is on an edge, you quickly determine the correct line of position on a chart for that bearing. A see-through acrylic sheet overlays and protects the chart as you plot and allows for notations using a dry erase marker (included). A tough custom nylon carrying case is included. Weight 1lb. 10oz. Dimensions 22-5/8" x 20-3/16".