MD-3003b1 is a high performance hand held metal detector designed to meet the exact requirements of the security industry. Typical uses will include body search for offensive weapons in crowd control, airport and border security, checking parcels and letters for metal objects and anywhere that hidden metal needs to be detected. Technical Specifications: Power Voltage: 9V(6F22) standard or rechargeable battery Power: 270mW Operate Frequency: 22KHz Operate Current: < 50mA Operating Voltage: 7V-9V Net Weight: 409g Dimension: 41(L) X 8.5(W) X 4.5(H)cm Indicator Visual: Red / Green LED Detecting way: Speaker or Earphone;(Earphone not included), vibration Control On/Off Switch; Low sensitivity Switch Sensitivity Adjuster Maximum detection range: Object low sensitivity optimum sensitivity 38 caliber hand gun 15cm 20cm pen knife 10cm 15cm Razor blade: 5cm 10cm