... use BenefitsMD-300 metal detector is a mini-type hand held metal detector, mainly for security check in important ... ON: mode of vibrationIndicatorsFlashing yellow LED low battery indicatorFlashing red LED Alarm Flashing green LED Power on SpecificationOperating frequency,20kHzWeight,272g ... ,1. 1/2 pin,10mm2. Model 64 pistol, 150mm3. 6" dagger, 150mm4. 8mm (diameter),40mm5. Aluminum & copper sheet ...