The Professional Handheld Security Metal Detector Wand is designed for the rigorous requirements of security environments, including airports, correctional facilities, schools, concerts, sporting events, and public and private buildings.Specifications Speaker will sound when metal is detected 2 Mode Slide Switch: Audible mode - Silent mode [Threshold] screw adjust detection strength Green power LED indicates unit is on Red LED will light when metal is detected 360 degree detection area 9V battery compartment (Battery not included) DimensionsRing: Outer: 150 x 25 x 25mm Inner Diameter: 90mm Handle: 355 x 28 x 25mm How to Detect MetalUse either audible mode and silent mode and hover the scanner in close proximity to the surface area while sweeping. If metal is detected, the red LED will light and/or the speaker will sound a constant tone.How to Adjust the SensitivityUse a slotted screwdriver to adjust the threshold. Rotate the screw clockwise to increase the detection strength.How to Install the BatteryUnscrew the phillips head, slide the cover off, and install a 9V battery.