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