In addition to dual sensor models with redundant detection and independent outputs, ML6 Series includes long-range background suppression sensing models and retroreflective models with no sensing deadband. All non-through-beam units feature integrated cross-talk immunity to make side-by-side mounting possible, tamperproof design, 4-in-1 output to minimize inventory and wiring, and immunity to ambient light. Diagnostic LEDs in front and back of housing provide status indication.