Suitable for all vehicles, boats, and off-road vehicles. The signal comes directly from the satellite signal receiver (GPS speed sensor). The gauge has the advantages of high precision, quick location confirmation, and short start-up time. IP67 waterproof and dustproof stepper motors used for the full range of stepping gauges, great features with less power consumption, longer life, higher precision, etc. Installation: 1. Power it on, then it will search for the signal and the LCD will display \"gps---\". If there is still no GPS signal after three minutes, the LCD will display \"Err\". 2. Short press the button to change the backlight color: The backlight changes in order: red (default) green blue white yellow cyan purple (automatic). Automatic: Automatically change the backlight color every 20 seconds, cyclically switching according to the above sequence. Wiring 1 Black: Ground (-) 2 Red: 9-30VDC 3 Yellow: Backlight Indication range: 0-60 Color: Silver Backlight: 7 colors Material: Stainless steel + plastic Size: 85 mm Package contents: 1 x GPS speedometer; 1 x 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 +/- 1-3 cm.