Real-time measurement of the vehicle roll and pitch angle during driving, the range is -40~ +40. The current altitude of your car can be measured. GPS satellite positioning, make sure you don't go in the wrong direction. Perfect for traveling and driving adcentures. Obtain the current driving speed, with over speed alarm function, as well as display the local time. Real-time voltage monitoring, can avoid safety hazards caused by too high or too low voltage, prolonging the lifespan of the battery. Suitable for all vehicles, such as caravans, trucks, buses, cars, off-road cars, SUVs, and other Vehicles. Plug & Play: 1. Plug the power line into the car lighter port; 2. Connect the power line to the data part; 3.Place the device horizontally in a visible position and fix it with glue. Colour:Black Material:plastic Package Contents: 1 x Car Hud Display 1 x English manual Only the above package content, other products are not included. Note: Light reflection 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.