How to use it?

Just pop the joint ball onto the mounting bracket that comes with your Garmin GPS.
Insert the blade onto the CD slot, then tighten the nut.

Reminder

Some batches of the mounting bracket, Garmin Nuvi origin or after market, may be a little larger. In this case, please do a little DIY with the mount: wrap the ball joint with a piece of tape or paper or tissue then pop it into the bracket.