Specification: -Power: DC 10V~30V-Depreion&Elevation angle: -40 +40-Clock Error Value: < 1 minute-Voltage measurement accuracy: O.5V-GPS Cold Boot Time: 32s (average)-GPS Data Refresh Time: 1s-Working Temperature: -40 ~ +80-Roll Angle:-40 +40-Voltage Measurement Range: DC5V~30V-Speed Accuracy: < 0.36Km/h-GPS Hot Boot Time: 1s (average)-Wirele Transmiion Frequency:2.4GHz-Product Size:170*68*60(mm) Package Included: 1*X90 HUD1*Cigare lighter1*Fixed pad1*Instruction manual1*Packing box 1.How To Switch From Miles To Km? it supports both MPH/h and KM/hPre M , switch MPH/h inch and KM/h metric(Note: Altitude is in feet in MPH/h mode and meters in KM/h mode)(Explanation: MPH/h icon lights up to MPH/h Mode, MPH/h icon is off to indicate KM/h mode) 2.How to adjust the time? In the state of power off, pre the power button. After the screen lights up, pre and hold the M button / power button 3-4 seconds immediately1. Decrease time: Long pre the M key will automatically enter the time adjustment interface.M key (left): adjust the hour hand, power button (on the right): adjust the second hand.2. Add time: long pre the power button.some country's time is slower /faster than GPS time some hoursYou can adjust time according to the user manual Vehicular intelligent Horizontal slope meter Alarm reminder/Fully automatic detection of vehicle driving condition Improve driving safety GPS satellite altitude instrument GPS compa and theodolite Smooth driving Pitch Angle: -40 to +40 Roll Angle: -40 to +40 Safety digital speed instrument Schedule display Battery voltage real-time monitoring Automatic dimming for HD display Product Function: 1 Precisely shows vehicle tilt angle with clear notification, when the angle is over 40, alarm alerts.2 Precisely show vehicle pitch angle changes,when the angle is over 40the alarm alerts to insure your safety.3 After connected to power supply, there will be backlight inside, which will help you see accurately in case of night or dark situation.4 Elevation error within 5- 100 meters.5 After the vehicle starts the speedometer starts automatically, after car parking the meter will be in sleep mode automatically.6 . Over speed alarm:Fatigue driving alarm alerts after driving for 4 hours.7 Fatigue driving alarm alerts after driving for 4 hour Feature 1 Applicable to Asian cars, American cars, European cars.2 Equipped with high-precision satellite GPS signal module.3 Automatically monitor vehicle driving conditions.4 Adjust the brightne of the screen by using the sensitivity of the light sensor.5 Free rotation, which is more sensitive.6 It adopts color HD LCD display with high resolution.