The RAP-300-1U, RAM Magnetic Power Plate III, is designed to hold various devices including radar detectors and cellphones. The magnetic plate includes two powerful rare earth magnets, composite cradle and one adhesive metal plate. To mount your device to the magnet, you will need to attach the metal plate to the back of you device. Includes a rectangular 50mm x 38mm x 0.08mm thick metal plate with adhesive back.