|Contraband detection systems allow agencies and officers to detect and diffuse potential threats. Research and development efforts are under way on systems that detect a variety of contraband, from drugs to human beings to concealed weapons. Because concealed weapons—principally handguns and edged weapons—pose a potentially lethal threat to law enforcement and corrections personnel, a number of research projects are focused on their detection. Current detection systems include portal-type metal detectors (as encountered in airports and many office buildings) and metal-detecting wands. Despite limitations—e.g., limited range, high false-alarm rates, obtrusiveness—these devices have provided a certain margin of safety in areas such as prison visitor areas, government offices, courts, and schools.