Optex AX-350TF long range photoelectric detectors with selectable beam frequencies. The selectable beam frequencies can be used to avoid unwanted crosstalk that can occur when using multiple photobeams over long distances or beam stacking applications. Also the AX-TF Series employs multiple beam technology and utilizes an AND circuit that requires all beams to be interrupted simultaneously before an alarm is generated. This reduces false alarms due to accidental beam interruption by falling leaves and small animals. Model: AX-350TF detection range 100m. Model: AX-650TF detection range 200m