Features: This high precise slide rule delivers accurate measurements and versatile electronic proportional scaling, solving issues with traditional tools like wear and inaccurate readings for navigation and plotting tasks. Crafted from lightweight plastic with clear markings, it ensures easy handling and long lasting performances without causing fatigue during extended use. Designed for students, professional, and enthusiasts in aviation, and technical fields, this navigational tool supports quick learning and reliably application in training and work environments. Ideal for scenarios such as flight navigation, marine charting, and technical drawing, its compact design allows effortless portability in backpacks or tool set for on the go efficiency. Featuring plastic build that minimizes environmental impacts, this proportional scale calculator enhances productivity with straightforward operations, perfect for beginners in labs or workshops. Specifications: Component: plastic Size:Approx.16.8x6.2cm/6.61x2.44inch Size:Approx.19.3x5.6cm/7.59x2.2inch Size:Approx.38.1x7cm/15x2.75inch Size:Approx.34x11.5cm/13.38x4.52inch Styles:CNP1/CNP2/CNP3/KCNP1 Lightweight and convenient, suitable for use in a variety of environments Package Includes: 1pcs Electronic Proportional Ruler note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you donot mind befores you order. 2.Due to the differences between different monitors, the picture may not reflect the actual color. Thanks for your understandings.