Handheld and light weight,easy to use. There is a battery undervoltage indication . It can be used for public security in airports, railway stations, docks, customs and frontier defense as well as quality control of medicine, food and other commodities. Sensitivity is easy to detect a metal object of size . Sensitivity can be adjusted according to site requirements. The alarm mode has two alarms: sound and light, vibration, high sensitivity. Simple operation, exquisite design, easy storage and low failure rate.