The Photoelectric Beams of OPTEX's AX-250/500PLUS Series combine precise detection capability with increased reliability providing superior outdoor detection. > A dual beam design incorporates synchronized pulsed signals, and an adjustable beam interruption time can virtually eliminate unwanted activation. A high level of detection accuracy will be maintained, no matter how harsh the environment. The AX-250/500PLUS will automatically compensate for changes in the surrounding conditions. The advanced mechanical design allows for easy installation and set-up providing long-term reliability, ideal for today's outdoor security systems. size="-1">