An external adjustment device for non-invasively adjusting an implant, the external adjustment device including a controller in communication with an actuator associated with the adjustable implant and a sensor configured to receive information from or about the adjustable implant. The external adjustment device may further comprise a power source and a display. According to one exemplary embodiment, the external adjustment device comprises a magnetic element configured to generate a rotating magnetic field； and a driver configured to drive the magnetic element to generate the rotating magnetic field and configured to rotate a permanent magnet of an adjustable implant, wherein upon placing the external adjustment device in proximity to an adjustable implant having a permanent magnet the magnetic element is configured to magnetically couple with the permanent magnet, and wherein the external adjustment device is configured to non-invasively determine one or more of a magnetic coupling state and a stalled state of the magnetic element and the permanent magnet disposed within the adjustable implant.
