- 12 Inch Parallel Ruler for plotting accurate bearings or course lines on nautical charts. It combines a protractor plotter and a basic parallel ruler to plot lines of bearing, degrees of a bearing line, or degrees of a course before charting, making it useful for meridian measurement routes on boats and ships. - Unmatched durability: built from clear acrylic with a brushed aluminum arm and a polished aluminum handle, providing long-lasting performance even with frequent use. - Precision and clarity: scales are clear and easy to read, engraved with full 180° protractor markings. When the arms are closed, the middle of the bottom edge forms the protractor center, giving you all essential tools in one compact design. - Unobstructed viewing: high transparency supports unobstructed viewing of information during use, improving accuracy in mapping and drawing. - Easy operation: hold the marine navigation parallel ruler in each hand and move parallel to each other alternately. The sturdy connector with appropriate tension can be used parallel to another ruler or as a reference, ensuring correct and smooth parallel drawing. - Specifications and use: 12 inches in length; acrylic body with brushed aluminum arm and polished aluminum handle; designed for marine navigation and chart plotting. - Practical applications: plotting course lines and bearings on nautical charts at sea; planning meridian routes in the chart room; assisting cartography or surveying tasks that require precise parallel line plotting.