Abstract: A reusable security tag for use on merchandise in department stores and like establishments has a housing which confines a locking device, a leaf spring and a signal generator. The locking device can receive the shank of a retaining member having a head which holds a portion of an article of clothing or other merchandise between itself and the housing. The locking device can release the shank by way of the spring in response to deformation of a selected component of the housing, or in response to placing of a magnet adjacent the housing so that the magnet can shift a ferromagnetic member which is reciprocably installed in the housing and can change the position of a reciprocable shaft forming part of the locking device.