Usage method: Push the power switch (8); a "click" or vibration means power is on (green light). No sound/vibration indicates no battery or poor contact. Continuous alarm means battery needs replacing. After startup, hold the handle to scan. Alarm and red light indicate metal detection; stop scanning to silence alarm and revert to green light. For low sensitivity: Press and hold switch (3) to ignore small metal objects. Alarm and red light indicate larger metal detection; stop scanning to revert to green light. 1. Safety detection and inspection of stations, sports venues, and docks 2. Security inspections of examination rooms, public security, schools, and security departments. Reminder:This product cannot be used to measure broken nails in wood, plastic lighters, gold and silver jewelry, colored or rare metals. Type:Scanner Condition: Power supply: rechargeable battery power waste: 270mW Working frequency 22KHZ Standby current:Less than 5MA Working voltage: DC 7-12V Working temperature: -10℃-+65℃ Colour:Black Material:Plastic Package Contents: 4 x Scanner 4 x 12V1ACharger 4 x 9V long UV charging station