Ritchie Voyager Flush Mount CombiDial Compass3" Dial with White Housing Ritchie Compasses provide accuracy from the inside out. When properly sized, installed and compensated a marine compass is the most important instrument on any boat. It will provide accurate, trouble-free heading references under the most adverse conditions without relying on electricity, radio signals or satellite communications. The most important criteria when selecting a compass are dial size and mounting style. Quality components aid accuracy, smooth response, stability and trouble-free operation. Modern technology makes Ritchie Compasses the World's Best Marine Compasses.• Type: CombiDamp Dial• Mounting Hole: 4-3/16 Inch• Dial: 3 Inch• Voltage: 12 Volt 3 Inch CombiDamp Dial 5-1/4 Inch Overall Width; 4-3/16 Inch Mounting Hole With Mounting Gasket, Built-In Compensator | Ritchie Voyager Flush Mount CombiDial Compass, White