... fast. * The human body induction system, 120°angle of view,distance is about 5m.* With mounting bracket, 180°adjustable angle ... and high power conversion rate, more than 90%* Powerful anti-jamming, it can work well even under the electromagnetism, ... bell... Speeding alarm , vehicle speeding alarm , overspeed alarm , alarm ,anti-theft alarm ,security alarm ,security system, bell, chime, door chime ...