Explorer Bulkhead Compass Features: 2 3/4" Easy to Read Direct Reading Dial Viewing is adjustable to 30 degrees 12V Night Illumination Built-in Compensators to Easily Adjust for Deviation Easily Installed, Fits 3" (7.62 cm) Mounting Hole. Scientifically Matched Sapphire Jewel & Hardened Steel Pivot Dial Movement Powerful DirectiveForce Magnets for Fast Heading Lock-on High Temperature Composite Construction for Extended Operating Range 100% Repairable Exclusive 5-Year Ritchie Warranty