The SM91EN/RN series rugged powerful VALU-BEAM® opposed mode Emitter/Receiver Pairs designed to function in difficult environments. Excess gain is conservatively rated at 100x at an emitter-to-receiver separation distance of 3m (10ft). Receivers will not false-trigger when pointed directly into a light source of 120,000lux. Receivers are also immune to false triggering by sunlight reflected from water droplets and interference from flashing strobe lights as are typically found on plant lift trucks. Sensors are also immune to interference from a 5W handheld transceiver, operating on specified frequencies, held 6 inches away from the sensor. Emitters and receivers that are to be used together must carry the same modulation code designation (A, B or C). These sensors are ruggedly constructed in reinforced, moulded, PBT polyester housings with replaceable acrylic lenses.