Explorer Compass Features: 2 3/4" Easy to Read Direct Reading Dial * Easily Installed, Fits 3.75" (9.53 cm) Mounting Hole. * Internal Green Night Illumination * Built-in Compensators to Easily Adjust for Deviation * Scientifically Matched Sapphire Jewel & Hardened Steel Pivot Dial Movement * Powerful DirectiveForce Magnets for Fast Heading Lock-on * Movable Sun Shield * High Temperature Composite Construction for Extended Operating Range * 100% Repairable * Exclusive 5-Year Ritchie Warranty