Know The Apparatus:This unit is 3 in 1Metal/Voltage/Stud Detetor.It uses electronic signals to locate the exact position of studs,ceilling joist AC wires and metal throughDrywall,concrete and other common wall materials .Once the edge of a stud has been detected ,it emits audio and visual signals (LCD Display) that allow you to easily pinpoint its center position .This unit is an ideal tool for DUY fans ,professional eletrician and user in decoration field.Function Description1.Detect STUD2.Detect metal3.Detect AC Live Wires4.Using metal detect function to find hidden metal pipe,rivet or fixture in the wall5.Auto power off (No operation 30 seconds )SpecificationBattery power :6F22 9V battery(the battery is not include)Stud Detecting depth:Wood 30*30mm:18mmMetal Detecting depth:iron pipe 25mm:30mmAC live Wires:AC 90~250V live wire(5cm),frequency at 50~60 HzOperating temperature & humidity: -7C ~ 40C, <75%Storage temperature & humidity: -20C ~ 50C, <85%Size: 155(L)* 72(W)* 28(H) mmWeight: about 203g