Metal detector gate (Metal detection door, arched walkthrough metal detector / doorframe metal detector gate / WTMD / DFMD) is a detection device for detecting metal objects carried by personnel walking through the detector gate. Walkthrough metal detector security doors are mainly used in 1) public places: including sports, entertainment (disco, dance halls, etc.), airports, railway stations, bus stations, ports, galleries, museums, banks, oil depots, power stations, conferences and other populated large public places for people to hide the body to check metal items such as guns, knives and other. 2) government departments include: police, prosecution, courts tribunals, prisons, detention centers, labor camps, drug rehabilitation and so on. 3)manufacturing companies: including electronic (such as: hard drives, mobile phones, MP3, through translation, voice recorder, electronic devices etc.), wire and cable, electrical appliances, gold and silver jewelry, cigarettes, pharmaceuticals, ink cartridges, mining, metal products, electroplating, pressure casting, plumbing equipment, precious metals (copper, aluminum, etc.) and processing and other related industries.