Widely used for maintaining precisely bearing line during onboard navigation planning, coastal map exercise, or educational marine navigation workshop where millimeter accuracy matters Its light weight design withstands saltwater exposure while providing portability between ship bridge, navigation station, and training facilities Suitable for professional navigators, marine cartographers, and sailing enthusiasts requiring professional parallel drawing ruler measuring tool for complex course calculation during voyages or detailed charting task Features copper acrylic construction with polishing, the mutifunctional parallel ruler flexible operate and stable alignment for seamlessly chart plotting in demanding marine environment Engineered for marine navigation, this 450mm parallel ruler combines high transparency acrylic and copper spacers, ensures accurately azimuth measurements and clearly scale visibility on navigation chart, Manufacturer: ZBIianxer