Ritchie F-50 Explorer Compass (Flush Mount) - Black 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;