Parts List: 1 x Metal detector 1. This unit is 3 in 1 metal/voltage/stud detector. 2. It uses electronic signals to locate the exact position of studs. 3. Ceilling joist AC wires and metal through drywall, concrete and other common wall materials. 4. Once the edge of a stud has been detected, it emits audio and visual (LCD display) that allow you to easily find out its center position. 5. This unit is an ideal tool for professional electrician and user in decoration field. Detailed description: Battery power: 6F22 9V battery (not included) Stud detecting depth: Wood 30 x 30 mm: ≤18 mm Metal detecting depth: iron pipe Φ25mm: ≤30 mm AC live wires: AC 90-250V live wire (5 cm), frequency at 50-60 Hz Operating temperature/humidity: -7ºC-40ºC,