Navigator Compass. Navigator Compass Features: 4-1/2″ PowerDamp Flat Card Dial with Large Numerals, Easily Installed, Fits 4.75″ (12.07cm) Mounting Hole, Exclusive Built-in Green NiteVu Night Illumination, Built-in Compensators to Easily Adjust for Deviation, Scientifically Matched Sapphire Jewel and Hardened Steel Pivot Dial Movement, Powerful DirectiveForce Magnets for Fast Heading Lock-on, Movable Sun Shield, 45 Degree Lubber Lines, High Temperature Construction for Extended Operating Range, Custom Fitted Protective Covers Available, 100% Repairable,