Defender receiver antenna* is capable of covering 3 - 5 foot aisle widths depending upon the type of tag or labels used. Wider aisles require additional pedestals. It uses SenTech's latest Swept RF receiver PCB with Digital Signal Processing (DSP) to maximize detection while virtually eliminating false alarms. Operates at both 8.2 or 9.5 MHz. Includes internal audible and visual alarms.