Abstract: A security label comprised of at least two magnetically soft materials having different coercivities but similar thresholds of magnetic saturation.

Abstract: Security apparatus for detection of a security tag to be hidden in an article to be detected. The digitized waveshape of a tag signature signal preferably obtained by distortion of an oscillating magnetic field, (whereby the distortion signal being detected constitutes a signature signal) is compared with a stored digital representative of a signature signal, and an alarm enable signal is generating in the event of correlation a predetermined number of times in a predetermined time period. The stored signal is modified by the specific factors. The characteristics of the apparatus and of environmental factors. The result is a reliable detection apparatus with a very low false alarm rate.