Universal Metal Plate: Compatible with all magnetic car mount holders as a non-magnetic accessory. | Package includes: Rectangle: 1.77" x 2.56" (4 pieces); Round: Diameter 1.57" (4 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 require. | 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.