1. Product function/purpose: A. There is a 3.0 positioning accessory at the bottom, which can be installed with a 1/4 positioning hole. 2. Features and selling points: 1. The bottom magnetic suction can fold two cards. 2. Mini and light. 3. 1/4 positioning hole;<br><br> Made of High Quality Meterial, Stronger And More , Improve The Appearance Easy to use,Easy to replace Color: Black Material: Aluminum Alloy<br><br>Package Contents: 1*Magnetic Quick Release Adapter<br><br>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.