Park the car on a level surface, attach the adhesive to the product, adjust and secure it in the vehicle for optimal horizontal positioning. Connect the power supply and wait for the satellite GPS signal to be received until the data displays normally. Press and hold the setting button, then click to adjust the electronic clock. Press and hold the button, then click the setting button to adjust the time on the X90. Accurately displays vehicle tilt angle with clear notification; an alarm will sound if the angle exceeds 40 degrees. Precisely shows vehicle pitch angle changes; an alarm will activate if the angle exceeds 40 degrees to help ensure safety. After connecting to the power supply, the device provides internal backlighting for improved visibility in low-light or nighttime conditions. Elevation error range is within 5100 units. Once the vehicle starts, the speedometer activates automatically; after parking, the device enters sleep mode automatically. Features include an overspeed alarm and a fatigue driving alert that activates after 4 hours of continuous driving.Power: DC 10V30V Tilt and elevation angle range: -40 to +40 Clock error value: Less than 1 Voltage measurement accuracy: 0.5V GPS cold start time: 32 seconds (average) GPS data refresh rate: 1 second Operating temperature: -40C to +80C Roll angle range: -40 to +40 Voltage measurement range: DC 5V30V Speed accuracy: Less than 0.36 km/h GPS hot start time: 1 second (average) Wireless transmission frequency: 2.4 GHz Product dimensions: 170 x 68 x 60 mm Color: Black Material: Plastic + Polycarbonate Package Contents: 1 x Head-up display Note: Light reflection and differences in display screens may cause slight variations in the item's color as seen on screen compared to the actual product. Measurement tolerances allow for a 13 cm variation.