This motion detection system helps employees be safer around exterior doorways. It includes both an indoor and outdoor sensor that activate a visual alarm on the opposite side of the doorway when they spot approaching vehicles or pedestrians. This warns workers about potential collision hazards for those passing through or in front of the doorway, as well as other dangers such as unauthorized persons on the property after hours. By signaling only when it senses motion in two directions, this system avoids going off more often than it needs to, which helps to keep people from becoming accustomed to it and failing to notice it. You may add extra sensors if you need to monitor movement in a greater coverage area, indoors or outdoors. Power is supplied through a pre-installed power cord; see cord length options below.