[Functions]  ⊙ Sensitivity:super sensitive, a tiny metal piece like a paper clip can be detected;  ⊙ Anti-resistance:resistance can be removed by adjusting button;  ⊙ Self-diagnosis:auto diagnosis when starting, no need to adjust;  ⊙ Alarm:by sound, buzz and light;  ⊙ Recognition function:to distinguish the size and distance of the objects by colors green, yellow and red; to distinguish the size and distance of the objects by sound.  ⊙ Work mode:only bigger size metal item will alarm while using low-sensitivity mode (keeping pressing this button while detecting)  ⊙ Applications:High decibel designing to use in noisy environment[Specification]  Working voltage:One standard 9V alkaline battery  Working frequency:95KHZ  Working environment:-20℃ - +55℃  Adjusting:Automatic  Dimension:420mmx41.3mmx83mm  Weight:0.5Kg