A wearable device for attachment to the ear of a user can comprise an earpiece including a speaker and a body section including a hook for attachment about the ear of a user. The length of the earpiece can be adjusted. The earpiece can rotate relative to the body section. The point of rotation can be located within a region defined by the perimeter of the concha of the ear of a user. The wearable device can comprise magnetic elements configured to magnetically couple through the user's ear to retain the wearable device in place. A magnetometer which is configured and arranged to detect a degree of magnetic coupling between the magnetic elements is disclosed.