Quantity: One PieceWide Detection Range: The Maximum Detection Range Is 3 Inches (3 Inches) For Metal Parts And 5 Cm (2 Inches) For Bolts. Simply Find The Center And Edge And Identify Metal Pipes, Live Wire Studs, Timber Framing, Hidden Beams Behind Walls, Floors Or Ceilings.Search Center: When Live Wire Monitoring, A Warning Sign With Ac Wire Is Displayed On The Lcd. Three Sensing Modes Indicate Strength, Close To Ankle, Center, Highest Post As Center, And The Ankle Beep Will Remind You When You Reach Your Destination.Calibration: Press Scan Button And Hold For 1-2 Seconds Before Testing. And Calibr. Beeps Will Remind You When Your Job Is Done. You May Need To Recalibrate Your Device If The Button Is Accidentally Unlocked Initially Or If You Feel It Is Necessary During The Process.Excellent Screen Backlight: Lcd Backlight Provides A Clear And Displayed Appearance Detection Patterns Even In Low Light Conditions. When The Battery Is Low, The Audio Display Will Beep To Alert You.,"