Hand Held Metal Detector MD-3003B1 1.high performance 2.Scan Rate 75-600mm per second 3.9V Volt rechargeable battery Hand Held ... the red light coming on,if the detector is held still over a metal object the detection signal ... a Pistol, Knife,ect and will not respond to small metals such as a coin,key ,hat pin, etc ... a dry warm environment. Good Service and Best Quality Hand Held Metal Detector MD-3003B1