Product Introduction: MD-3003B1 is a small hand held metal detector for security checking. It is easy to use, without any adjustment controller, fast response to detect metal objects, sound and LED light mitting alarm simultaneously. A clear low frequency tones sound can be heard when detect small metals, and high audio tone can be heard when detect large metal objects. Product Parameters: 1.Alarm Indication : Audio alert and LED indicator work together 2.Sensitivity :3cm(for a RMB one YUAN Coin) 3.Power Supply:9V fold battery (6F22ND),Low battery indication, can connect with recharger,(recharger is optional accessory ) 4.Quiescent Current :