Used Sensormatic Antennas...

The Ultra Post II primary antenna protects up to three foot exits in both directions While an Ultra Post II two antenna eas system with both a Primary and a Secondary can Protect up to a six feet exit between antennas and three feet on the edges.
The Digital ProMax Single Antenna system reprtedly protects up to four feet exits in both direction. Digital DoorMax two antenna systems protect up to six feet exit between antennas. All these systems work with AM security tags and labels. The most popular tag for these systems is the Sensormatic Supertag, followed by the UltraGator tag.