1. Suitable for all vehicles, boats and off-road vehicles 2. The signal comes directly from the satellite signal receiver(GPS Speed Sensor) 3. The gauge has the advantages of high precision, quick location confirmation and short start up time. 4. IP67 waterproof and dustproof grade 5. Stepper motors used for full range of stepping gauges, great feature with its less power consumption, longer life, higher precision, etc. Fixing dimension: 85mm(3-3/8 inch) Backlight: 7 Color installation : 1.Turn it on, then the to search the signal and LCD will display "gps-",if there is still no GPS signal after three minute, LCD displays "Err". 2.Short press the button to change the backlight color: Backlight changed in sequence: red (default) - green - blue - white - yellow - cyan - Purple - (automatic).Automatic: Automatically switch the backlight color every 20 seconds, Cycle switch according to the above sequence. Wiring 1 Black: Ground(-) 2 Red: 9-30VDC 3 Yellow: Backlight Indicating Range: 0-30 mile Model: CX8133-BN Material:Stainless steel + plastic colour:Black Package Contents: 1 * GPS speedometer 1 * GPS antenna Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.