Specification: high detectivity and speed of detection that can be widely used in security inspection and theft protection places. Functions: (1) High sensitivity with audible and visual alarm. (2)Only one button switch, easy to be operated. (3) Thimbleful electric current consumption: alert 0 mA, working less than 1mA, alarm 6.5mA (4) Rapid detection: reset and finding a new target after last alarm needs only 0.1 second. (5) Low voltage indication: continuous checkout of the power and indicate by the red LED light when voltage is low. Technical parameters: (1)Working temperature: -20℃-65℃ (2) Working humidity: 98% (3) Power switch: push-button switch (4) Alarm indicator: speaker and red or green light LED (5) Detection speed: 0.1 second per time (6) Battery: 1 x 9v battery (7)Size: 41cm (L) x14cm (Diameter of the detection circle) x2.8cm (H) (8) Weight: about 280g