Switchable Speed Unit: Marine Speedometer can freely switch the speed unit of kont, mph, km/h, which is convenient for you to watch and provides you with more convenience Display Function: SOG: Ground Speed; TRIP: Single Mileage, Cleared when Power Off; ODO: Accumulated Mileage, Saved when Power Off; COG: Heading, Clockwise Angle of True North; 9-30VDC Working Voltage, Speed Meter Gauge is IP67 waterproof Wide Range of Application: The navigation pointer supports 8 direction pointers. Universal Digital GPS Speedometer is suitable for ships, yachts, trucks, commercial vehicles, construction machinery Easy to Assemble: Small, light and easy to install, no other complicated steps are allowed, bringing you more convenience. Wiring Connection: Black Line: Negative Power Supply (-); Red Wire: 9-30VDC Durable Material: Stainless steel material, waterproof, durable, has long service life, not easy to damage. If you have any problem about our 85mm Speedometer Digital Gauge, please feel free to contact us