Features The sensitivity is determined primarily by the size,shape of the goods Indicator: BZ, vibration motor Three-position switch with selection of visible alarm, audible and visible alarm and power supply controlling is convenient, smart, fast Control: circulation switch (on, o, a sound of light or mode of vibration) Optional earpiece output for audible alarm, available in noisy and quiet environment Highly sensitive, detect ferrous and non-ferrous and stainless steel weapons Sound and light alarm simultaneously Alkaline cell (7V - 9V) can work over 40 hours and distance does not change Warn automatically when short of voltage Simple, convenient to use, easy to adjust Description The HMD-88 is a high performance Hand Held Metal Detector, Designed to meet the exact requirements of the security industry.