This device is one of the most advanced perimeter detectors. Infrared beams that are continuously sent between the transmitter and the receiver are used to detect the intrusion. Due to the large distance between the transmitter and the receiver, active infrared detectors can be used to effectively protect even large rooms. In the case of detectors offered by SATEL, adequate protection from the effects of atmospheric conditions allows the device to be applied outdoors to detect a potential intruder entering the protected area.