Details
KanPas V28 Mini Automotive Dashboard Car Ball Compass (Black)

Features: mini size, shockproof, waterproof, accurate pointing
The reading method of ball compass is opposite to the pointer compass, the direction of the ball compass you see is the direction the car is heading.
Installation instructions: First determine the correct direction outside the car, other reference compass should be separated from the ball compass by more than 20 inch.
Then find a suitable position in the car so that the direction of the ball compass is the same as that outside the car.
Finally, tear off the double-sided tape to fix the ball compass.