1. The vacuum water system guide ball reminds you of the actual direction. 2. Use double-sided tape to paste it on the dashboard, which looks clear at a glance. 3. Made of high-quality ABS, the surface is very smooth. 4. The size is small and does not take up space. 5. Note: The pointing is not accurate when placed in the car. It is usually caused by the magnetic field interference in the car. Change the position and try slowly to find a suitable position. It is recommended not to have more than 2 guide balls together because they will interfere with each other and affect the pointing.