Universal Metal Plate: Easy to use with all magnetic car mount holders. | Package Includes: Rectangle: 1.77" x 2.56" (6 pieces); Round: Diameter 1.57" (6 pieces). | Strong Adhesive: Each metal plate features strong adhesive tape, making it easy to stick onto the back of your phone or case without any hassle. | Wide Compatibility: Since all of the metal plates are not magnetic on their own, we strongly recommend using them in conjunction with universal magnetic mounts wherever you need them. | Important Note: A metal plate may disable wireless charging if it is attached to the back of your phone or case. It is suggested to remove the case when using wireless charging.