AM labels(Acousto Magnetic, AM)
AM tags are made of two strips of metal that are magnetized for activation. The transmitter pedestal sends out 58 kHz pulses, which cause the metal to oscillate.

Q: What are the benefits of using Acousto Magnetic (AM) labels?
A: Acoustic Magnetic (AM) system is one of the most widely used electronic anti-theft system, giants such as Wal-Mart, SaSa, PARKnSHOP, IT also sdopt the AM system in reducing shop theft.
Original Sensormatic AM Labels are: 1) Easy for deactivation 2) No false alarm 3) Small in size.