Sierra 781-684-035P Eclipse Series GPS Speedometer Features Dial Range 0-35 MPH Size 3 Included LCD heading display to show course over ground Use our GPS antenna sold sep or connect to an existing NMEA 0183 GPS device - connectors included Speed accuracy of -1 MPH once moving Heading accuracy of -1 degree once moving Ideal for slow speed apps like pontoon boats and for high speed performance boats w pitot tubes Scratch-resistant domed glass lens Perimeter lighting for excellent readability at n