With its built-in prism, this compass allows you to read a bearing without shifting your eyes off your mark—you get more accurate bearings faster and without eyestrain. Dial and needle are photo-luminescent, no batteries required; recharge in sun or other bright light. Ruggedly built with a soft expansion diaphragm to prevent leaks and bubbles. Very hard crystal resists scratches that can make compass hard to read. Waterproof. 1° gradations. Configuration: Puck style Sighting System: Infinity prism Illumination: Photo luminescent lighting 3.3"dia. x 1.3"H Five-year warranty