How to treat gossip fingertip gyro?

The index of the red pointer is the required degree. According to Baidu Encyclopedia, aim the fingertip gyro compass at the direction to be measured, fix the position of the reticle, and then move the inner disk with both thumbs. When the inner disk rotates, Tianchi will rotate with it until the magnetic needle stops and coincides with the red line of Tianchi. Read the number of the red pointer, which is the required degree.